PAGE 1 000 A000000 10/31/2017 000 C000000 0001223026 000 D000000 N 000 E000000 NF 000 F000000 Y 000 G000000 N 000 H000000 N 000 I000000 6.1 000 J000000 A 001 A000000 PIONEER MUNICIPAL HIGH INCOME TRUST 001 B000000 811-21321 001 C000000 6177427825 002 A000000 60 STATE STREET 002 B000000 BOSTON 002 C000000 MA 002 D010000 02109 003 000000 N 004 000000 N 005 000000 N 006 000000 N 007 A000000 N 007 B000000 0 007 C010100 1 007 C010200 2 007 C010300 3 007 C010400 4 007 C010500 5 007 C010600 6 007 C010700 7 007 C010800 8 007 C010900 9 007 C011000 10 008 A000001 AMUNDI PIONEER ASSET MANAGEMENT, INC. 008 B000001 A 008 C000001 801-8255 008 D010001 BOSTON 008 D020001 MA 008 D030001 02109 010 A000001 AMUNDI PIONEER ASSET MANAGEMENT, INC. 010 B000001 801-8255 010 C010001 BOSTON 010 C020001 MA 010 C030001 02109 010 A000002 BROWN BROTHERS HARRIMAN & CO. 010 C010002 BOSTON 010 C020002 MA 010 C030002 02110 011 A000001 AMUNDI PIONEER DISTRIBUTOR, INC. 011 B000001 8-41256 011 C010001 BOSTON 011 C020001 MA PAGE 2 011 C030001 02109 011 C040001 1820 011 A000002 UBS INVESTMENT BANK 011 B000002 8-022651 011 C010002 STAMFORD 011 C020002 CT 011 C030002 06901 011 A000003 RBC CAPITAL MARKETS CORP. 011 B000003 8-045411 011 C010003 MINNEAPOLIS 011 C020003 MN 011 C030003 55402 011 C040003 4422 011 A000004 ADVEST, INC. 011 B000004 8-21409 011 C010004 HARTFORD 011 C020004 CT 011 C030004 06103 011 A000005 JANNEY MONTGOMERY SCOTT, LLC 011 B000005 8-462 011 C010005 PHILADELPHIA 011 C020005 PA 011 C030005 19103 011 C040005 1675 011 A000006 MCDONALD INVESTMENTS, INC. 011 B000006 8-30177 011 C010006 CLEVELAND 011 C020006 OH 011 C030006 44114 011 C040006 2603 011 A000007 STIFEL, NICOLAUS & CO., INC. 011 B000007 8-001447 011 C010007 ST. LOUIS 011 C020007 MO 011 C030007 63102 012 A000001 AMERICAN STOCK TRANSFER & TRUST CO. (COMMON) 012 B000001 85-00000 012 C010001 BROOKLYN 012 C020001 NY 012 C030001 11219 012 A000002 DEUTSCHE BANK TRUST COMPANY AMERICAS (PREF) 012 B000002 85-00000 012 C010002 NEW YORK 012 C020002 NY 012 C030002 10005 012 A000003 DELETE 013 A000001 ERNST & YOUNG LLP 013 B010001 BOSTON 013 B020001 MA 013 B030001 02116 015 A000001 BROWN BROTHERS HARRIMAN & CO. PAGE 3 015 B000001 C 015 C010001 BOSTON 015 C020001 MA 015 C030001 02110 015 E010001 X 015 A000002 CITIBANK, N.A. BUENOS AIRES BRANCH 015 B000002 S 015 C010002 BUENOS AIRES 015 D010002 ARGENTINA 015 E040002 X 015 A000003 HSBC BANK AUSTRALIA LIMITED 015 B000003 S 015 C010003 SYDNEY 015 D010003 AUSTRALIA 015 E040003 X 015 A000004 UNICREDIT BANK AUSTRIA AG 015 B000004 S 015 C010004 VIENNA 015 D010004 AUSTRIA 015 E040004 X 015 A000005 STANDARD CHARTERED BANK, BANGLADESH BRANCH 015 B000005 S 015 C010005 DHAKA 015 D010005 BANGLADESH 015 E040005 X 015 A000006 EUROCLEAR BANK SA NV 015 B000006 S 015 C010006 BRUSSELS 015 D010006 BELGIUM 015 E040006 X 015 A000007 NORDEA BANK AB (PUBL), FINNISH BRANCH 015 B000007 S 015 C010007 HELSINKI 015 D010007 ESTONIA 015 E040007 X 015 A000008 CITIBANK, N.A., SAO PAULO 015 B000008 S 015 C010008 SAO PAULO 015 D010008 BRAZIL 015 E040008 X 015 A000009 CITIBANK EUROPE PLC, BULGARIA BRANCH 015 B000009 S 015 C010009 SOFIA 015 D010009 BULGARIA 015 E040009 X 015 A000010 RBC INVESTOR SERVICES TRUST 015 B000010 S 015 C010010 TORONTO 015 D010010 CANADA 015 E040010 X 015 A000011 BANCO DE CHILE PAGE 4 015 B000011 S 015 C010011 SANTIAGO 015 D010011 CHILE 015 E040011 X 015 A000012 STANDARD CHARTERED BANK (CHINA) LIMITED 015 B000012 S 015 C010012 SHANGHAI 015 D010012 CHINA 015 E040012 X 015 A000013 CITITRUST COLOMBIA S.A., SOCIEDAD FIDUCIARA 015 B000013 S 015 C010013 BOGATA 015 D010013 COLOMBIA 015 E040013 X 015 A000014 UNICREDIT BANK AUSTRIA AG 015 B000014 S 015 C010014 VIENNA 015 D010014 CROATIA 015 E040014 X 015 A000015 CITIBANK EUROPE PLC, ORGANIZACNI SLOZKA 015 B000015 S 015 C010015 PRAGUE 015 D010015 CZECH REPUBLIC 015 E040015 X 015 A000016 SKANDINAVISKA ENSKILDA BANKEN AB (PUBL)DAN 015 B000016 S 015 C010016 COPENHAGEN 015 D010016 DENMARK 015 E040016 X 015 A000017 CITIBANK, N.A., CAIRO BRANCH 015 B000017 S 015 C010017 CAIRO 015 D010017 EGYPT 015 E040017 X 015 A000018 NORDEA BANK AB (PUBL), FINNISH BRANCH 015 B000018 S 015 C010018 HELSINKI 015 D010018 FINLAND 015 E040018 X 015 A000019 BNP PARIBAS SECURITIES SERVICES 015 B000019 S 015 C010019 PANTIN 015 D010019 FRANCE 015 E040019 X 015 A000020 BNP PARIBAS SECURITIES SERVICES, FRANKFURT 015 B000020 S 015 C010020 FRANKFURT 015 D010020 GERMANY 015 E040020 X 015 A000021 STANDARD CHARTERED BANK GHANA LTD. 015 B000021 S PAGE 5 015 C010021 ACCRA 015 D010021 GHANA 015 E040021 X 015 A000022 HSBC BANK PLC, ATHENS BRANCH 015 B000022 S 015 C010022 ATHENS 015 D010022 GREECE 015 E040022 X 015 A000023 STANDARD CHARTERED BANK (HONG KONG) LIMITED 015 B000023 S 015 C010023 KWUN TONG 015 D010023 HONG KONG 015 E040023 X 015 A000024 CITIBANK EUROPE PLC, HUNGARIAN BRANCH OFFICE 015 B000024 S 015 C010024 BUDAPEST 015 D010024 HUNGARY 015 E040024 X 015 A000025 CITIBANK, N.A.-MUMBAI BRANCH 015 B000025 S 015 C010025 MUMBAI 015 D010025 INDIA 015 E040025 X 015 A000026 CITIBANK, N.A., JAKARTA BRANCH 015 B000026 S 015 C010026 JAKARTA 015 D010026 INDONESIA 015 E040026 X 015 A000027 CITIBANK, N.A., LONDON BRANCH 015 B000027 S 015 C010027 LONDON 015 D010027 IRELAND 015 E040027 X 015 A000028 BANK HAPOALIM BM 015 B000028 S 015 C010028 TEL AVIV 015 D010028 ISRAEL 015 E040028 X 015 A000029 BNP PARIBAS SECURITIES SERVICES, MILAN BRANCH 015 B000029 S 015 C010029 MILAN 015 D010029 ITALY 015 E040029 X 015 A000030 SUMITOMO MITSU BANKING CORPORATION 015 B000030 S 015 C010030 TOKYO 015 D010030 JAPAN 015 E040030 X 015 A000031 BNP PARIBAS SECURITIES SERVICES 015 B000031 S 015 C010031 PANTIN PAGE 6 015 D010031 BELGIUM 015 E040031 X 015 A000032 DELETE 015 A000033 HSBC BANK MIDDLE EAST LIMITED,KUWAIT BRANCH 015 B000033 S 015 C010033 KUWAIT CITY 015 D010033 KUWAIT 015 E040033 X 015 A000034 DELETE 015 A000035 HSBC BANK MALAYSIA BERHAD 015 B000035 S 015 C010035 KUALA LUMPUR 015 D010035 MALAYSIA 015 E040035 X 015 A000036 BANCO NACIONAL DE MEXICO, S.A.(BANAMEX) 015 B000036 S 015 C010036 MEXICO CITY 015 D010036 MEXICO 015 E040036 X 015 A000037 CITIBANK MAGHREB 015 B000037 S 015 C010037 CASABLANCA 015 D010037 MOROCCO 015 E040037 X 015 A000038 BNP PARIBAS SERCURITIES SERVICES 015 B000038 S 015 C010038 PANTIN 015 D010038 NETHERLANDS 015 E040038 X 015 A000039 HSBC LIMITED, NEW ZEALAND BRANCH 015 B000039 S 015 C010039 AUCKLAND 015 D010039 NEW ZEALAND 015 E040039 X 015 A000040 STANBIC IBTC BANK PLC 015 B000040 S 015 C010040 LAGOS 015 D010040 NIGERIA 015 E040040 X 015 A000041 NORDEA BANK AB (PUBL), FILIAL I NORGE 015 B000041 S 015 C010041 OSLO 015 D010041 NORWAY 015 E040041 X 015 A000042 CITIBANK DEL PERU S.A. 015 B000042 S 015 C010042 LIMA 015 D010042 PERU 015 E040042 X 015 A000043 HSBC LIMITED,PHILIPPINE BRANCH 015 B000043 S PAGE 7 015 C010043 TAGUIG CITY 015 D010043 PHILIPPINES 015 E040043 X 015 A000044 BANK HANDLOWY W WARSZAWIE SA 015 B000044 S 015 C010044 WARSAW 015 D010044 POLAND 015 E040044 X 015 A000045 BNP PARIBAS SECURITIES SERVICES 015 B000045 S 015 C010045 PANTIN 015 D010045 PORTUGAL 015 E040045 X 015 A000046 HSBC BANK MIDDLE EAST LIMITED, QATAR BRANCH 015 B000046 S 015 C010046 ST. HELIER 015 D010046 QATAR 015 E040046 X 015 A000047 DELETE 015 A000048 AO CITIBANK FOR CITIBANK N.A. 015 B000048 S 015 C010048 MOSCOW 015 D010048 RUSSIA 015 E040048 X 015 A000049 DELETE 015 A000050 STANDARD CHARTERED BANK SINGAPORE BRANCH 015 B000050 S 015 C010050 SINGAPORE 015 D010050 SINGAPORE 015 E040050 X 015 A000051 DELETE 015 A000052 STANDARD CHARTERED BANK, JOHANNESBURG BRANCH 015 B000052 S 015 C010052 SANDTON 015 D010052 SOUTH AFRICA 015 E040052 X 015 A000053 CITIBANK KOREA INC 015 B000053 S 015 C010053 SEOUL 015 D010053 SOUTH KOREA 015 E040053 X 015 A000054 BANCO BILBAO VIZCAYA AREGENTARIA SA 015 B000054 S 015 C010054 MADRID 015 D010054 SPAIN 015 E040054 X 015 A000055 HSBC, SRI LANKA BRANCH 015 B000055 S 015 C010055 COLOMBO 015 D010055 SRI LANKA 015 E040055 X PAGE 8 015 A000056 SKANDINAVISKA ENSKILDA BANKEN AB(PUB) 015 B000056 S 015 C010056 STOCKHOLM 015 D010056 SWEDEN 015 E040056 X 015 A000057 CREDIT SUISSE (SWITZERLAND) LTD. 015 B000057 S 015 C010057 ZURICH 015 D010057 SWITZERLAND 015 E040057 X 015 A000058 BANK OF TAIWAN 015 B000058 S 015 C010058 TAIPEI 015 D010058 TAIWAN 015 E040058 X 015 A000059 HSBC LIMITED, THAILAND BRANCH 015 B000059 S 015 C010059 BANGKOK 015 D010059 THAILAND 015 E040059 X 015 A000060 CITIBANK ANONIM SIRKETI 015 B000060 S 015 C010060 ISTANBUL 015 D010060 TURKEY 015 E040060 X 015 A000061 HSBC BANK MIDDLE EAST LIMITED 015 B000061 S 015 C010061 DUBAI 015 D010061 UNITED ARAB EMIRATES 015 E040061 X 015 A000062 HSBC BANK PLC 015 B000062 S 015 C010062 LONDON 015 D010062 UNITED KINGDOM 015 E040062 X 015 A000063 DELETE 015 A000064 HSBC BANK (VIETNAM) LTD 015 B000064 S 015 C010064 HO CHI MINH CITY 015 D010064 VIETNAM 015 E040064 X 015 A000065 STANDARD CHARTERED BANK KENYA LIMITED 015 B000065 S 015 C010065 NAIROBI 015 D010065 KENYA 015 E040065 X 015 A000066 CITIBANK EUROPE PLC,DUBLIN-SUCURSALA ROMANIA 015 B000066 S 015 C010066 BUCHAREST 015 D010066 ROMANIA 015 E040066 X PAGE 9 015 A000067 CITIBANK EUROPE PLC,POBOCKA ZAHRANICNEJ BANKY 015 B000067 S 015 C010067 BRATISLAVA 015 D010067 SLOVAKIA 015 E040067 X 015 A000068 DELETE 015 B000069 S 015 B000070 S 018 000000 Y 019 A000000 Y 019 B000000 45 019 C000000 PIONEERFDS 020 C000001 0 020 C000002 0 020 C000003 0 020 C000004 0 020 C000005 0 020 C000006 0 020 C000007 0 020 C000008 0 020 C000009 0 020 C000010 0 021 000000 0 022 A000001 J.P. MORGAN SECURITIES LLC 022 B000001 13-3299429 022 C000001 20851 022 D000001 14886 022 A000002 BROWN BROTHERS HARRMIAN & CO. 022 B000002 13-4973745 022 C000002 4371 022 D000002 17914 022 A000003 SOUTHTRUST BANK 022 B000003 63-0022787 022 C000003 9582 022 D000003 1221 022 A000004 ALEXANDER CAPITAL, L.P. 022 B000004 13-3866977 022 C000004 5686 022 D000004 2375 022 A000005 CITIGROUP GLOBAL MARKETS INC. 022 B000005 11-2418191 022 C000005 1147 022 D000005 5770 022 A000006 FUNDS DISTRIBUTOR, LLC 022 B000006 26-1900768 022 C000006 5935 022 D000006 385 022 A000007 US BANK NATIONAL ASSOCIATION 022 B000007 31-0841368 022 C000007 5006 022 D000007 1015 PAGE 10 022 A000008 DAVIDSON KEMPER CAPITAL MANANGEMENT LLC 022 B000008 13-4021240 022 C000008 4500 022 D000008 0 022 A000009 FIRST TRYON SECURITIES, LLC 022 B000009 56-1986792 022 C000009 4078 022 D000009 0 022 A000010 JEFFERIES LLC 022 B000010 95-2622900 022 C000010 3225 022 D000010 0 023 C000000 72378 023 D000000 46293 024 000000 N 025 D000001 0 025 D000002 0 025 D000003 0 025 D000004 0 025 D000005 0 025 D000006 0 025 D000007 0 025 D000008 0 026 A000000 Y 026 B000000 Y 026 C000000 N 026 D000000 Y 026 E000000 N 026 F000000 N 026 G010000 N 026 G020000 Y 026 H000000 N 027 000000 N 028 A010000 0 028 A020000 0 028 A030000 0 028 A040000 0 028 B010000 0 028 B020000 0 028 B030000 0 028 B040000 0 028 C010000 0 028 C020000 0 028 C030000 0 028 C040000 0 028 D010000 0 028 D020000 0 028 D030000 0 028 D040000 0 028 E010000 0 028 E020000 0 PAGE 11 028 E030000 0 028 E040000 0 028 F010000 0 028 F020000 0 028 F030000 0 028 F040000 0 028 G010000 0 028 G020000 0 028 G030000 0 028 G040000 0 028 H000000 0 030 A000000 0 030 B000000 0.00 030 C000000 0.00 031 A000000 0 031 B000000 0 032 000000 0 033 000000 0 035 000000 0 036 B000000 0 038 000000 0 042 A000000 0 042 B000000 0 042 C000000 0 042 D000000 0 042 E000000 0 042 F000000 0 042 G000000 0 042 H000000 0 043 000000 0 044 000000 0 045 000000 Y 046 000000 N 047 000000 Y 048 000000 0.600 048 A010000 0 048 A020000 0.000 048 B010000 0 048 B020000 0.000 048 C010000 0 048 C020000 0.000 048 D010000 0 048 D020000 0.000 048 E010000 0 048 E020000 0.000 048 F010000 0 048 F020000 0.000 048 G010000 0 048 G020000 0.000 048 H010000 0 048 H020000 0.000 PAGE 12 048 I010000 0 048 I020000 0.000 048 J010000 0 048 J020000 0.000 048 K010000 0 048 K020000 0.000 049 000000 N 050 000000 N 051 000000 N 052 000000 N 053 A000000 N 054 A000000 Y 054 B000000 Y 054 C000000 Y 054 D000000 N 054 E000000 N 054 F000000 N 054 G000000 N 054 H000000 Y 054 I000000 N 054 J000000 Y 054 K000000 N 054 L000000 N 054 M000000 Y 054 N000000 N 054 O000000 N 055 A000000 N 055 B000000 N 056 000000 N 057 000000 N 058 A000000 N 059 000000 Y 060 A000000 Y 060 B000000 Y 061 000000 0 062 A000000 Y 062 B000000 0.0 062 C000000 0.0 062 D000000 0.0 062 E000000 0.0 062 F000000 0.0 062 G000000 0.0 062 H000000 0.0 062 I000000 0.0 062 J000000 0.0 062 K000000 0.0 062 L000000 0.0 062 M000000 0.0 062 N000000 0.0 062 O000000 133.1 062 P000000 0.0 PAGE 13 062 Q000000 0.0 062 R000000 0.0 063 A000000 0 063 B000000 8.1 064 A000000 Y 064 B000000 Y 065 000000 N 066 A000000 N 067 000000 N 068 A000000 N 068 B000000 N 069 000000 N 070 A010000 Y 070 A020000 N 070 B010000 N 070 B020000 N 070 C010000 Y 070 C020000 N 070 D010000 N 070 D020000 N 070 E010000 Y 070 E020000 N 070 F010000 N 070 F020000 N 070 G010000 Y 070 G020000 N 070 H010000 N 070 H020000 N 070 I010000 N 070 I020000 N 070 J010000 Y 070 J020000 Y 070 K010000 Y 070 K020000 N 070 L010000 N 070 L020000 N 070 M010000 N 070 M020000 N 070 N010000 N 070 N020000 N 070 O010000 Y 070 O020000 N 070 P010000 Y 070 P020000 N 070 Q010000 N 070 Q020000 N 070 R010000 N 070 R020000 N 071 A000000 33553 071 B000000 32821 071 C000000 388446 PAGE 14 071 D000000 8 072 A000000 6 072 B000000 9661 072 C000000 0 072 D000000 0 072 E000000 0 072 F000000 1190 072 G000000 89 072 H000000 0 072 I000000 8 072 J000000 3 072 K000000 0 072 L000000 8 072 M000000 7 072 N000000 0 072 O000000 0 072 P000000 0 072 Q000000 0 072 R000000 24 072 S000000 31 072 T000000 0 072 U000000 0 072 V000000 1 072 W000000 111 072 X000000 1471 072 Y000000 0 072 Z000000 8190 072AA000000 0 072BB000000 9188 072CC010000 9841 072CC020000 0 072DD010000 6831 072DD020000 0 072EE000000 0 073 A010000 0.3000 073 A020000 0.0000 073 B000000 0.0000 073 C000000 0.0000 074 A000000 0 074 B000000 0 074 C000000 0 074 D000000 387280 074 E000000 0 074 F000000 0 074 G000000 0 074 H000000 0 074 I000000 0 074 J000000 150 074 K000000 0 074 L000000 6178 074 M000000 5 PAGE 15 074 N000000 393613 074 O000000 0 074 P000000 45 074 Q000000 0 074 R010000 0 074 R020000 0 074 R030000 0 074 R040000 1637 074 S000000 100986 074 T000000 290945 074 U010000 22771 074 U020000 0 074 V010000 12.78 074 V020000 0.00 074 W000000 0.0000 074 X000000 4136 074 Y000000 0 075 A000000 0 075 B000000 292016 076 000000 11.74 077 A000000 Y 077 K000000 Y 077 Q010000 Y 078 000000 N 080 C000000 0 081 B000000 0 082 B000000 0 083 B000000 0 084 B000000 0 086 A010000 0 086 A020000 0 086 B010000 0 086 B020000 0 086 C010000 0 086 C020000 0 086 D010000 0 086 D020000 0 086 E010000 0 086 E020000 0 086 F010000 0 086 F020000 0 087 A010000 COMMON STOCK 087 A020000 723763108 087 A030000 MHI 087 B010000 PREFERRED STOCK - SERIES A 087 B020000 723763207 087 C010000 PREFERRED STOCK - SERIES B 087 C020000 723763306 088 A000000 N 088 B000000 N 088 C000000 N PAGE 16 088 D000000 Y SIGNATURE MARK BRADLEY TITLE TREASURER