PAGE 1
000 A000000 10/31/2012
000 C000000 0001223026
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 Y
000 H000000 N
000 I000000 6.1
000 J000000 U
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 C020100 PIONEER MUNICIPAL HIGH INCOME TRUST
007 C030100 N
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 PIONEER INVESTMENT MANAGEMENT, INC.
008 B000001 A
008 C000001 801-8255
008 D010001 BOSTON
008 D020001 MA
008 D030001 02109
010 A000001 PIONEER INVESTMENT 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 02109
011 A000001 PIONEER FUNDS DISTRIBUTOR, INC.
011 B000001 8-41256
PAGE 2
011 C010001 BOSTON
011 C020001 MA
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 PIONEER INVEST. MGT. SHAREHOLDER SVCS., INC.
012 B000001 85-01359
012 C010001 BOSTON
012 C020001 MA
012 C030001 02109
012 A000002 AMERICAN STOCK TRANSFER & TRUST CO. (COMMON)
012 B000002 85-00000
012 C010002 BROOKLYN
012 C020002 NY
012 C030002 11219
012 A000003 DEUTSCHE BANK TRUST COMPANY AMERICAS (PREF)
012 B000003 85-00000
012 C010003 NEW YORK
012 C020003 NY
PAGE 3
012 C030003 10005
013 A000001 ERNST & YOUNG LLP
013 B010001 BOSTON
013 B020001 MA
013 B030001 02116
013 B040001 5072
015 A000001 BROWN BROTHERS HARRIMAN & CO.
015 B000001 C
015 C010001 BOSTON
015 C020001 MA
015 C030001 02109
015 E010001 X
018 000000 Y
019 A000000 Y
019 B000000 56
019 C000000 PIONEERFDS
020 A000001 SANFORD C. BERNSTEIN & CO., INC.
020 B000001 13-4132953
020 C000001 6
020 A000002 UBS SECURITIES
020 B000002 13-2638166
020 C000002 1
020 A000003 MERRILL LYNCH, PIERCE, FENNER & SMITH
020 B000003 13-5674085
020 C000003 1
020 A000004 WELLS FARGO SECURITIES LLC
020 B000004 94-3379992
020 C000004 0
020 C000005 0
020 C000006 0
020 C000007 0
020 C000008 0
020 C000009 0
020 C000010 0
021 000000 8
022 A000001 JP MORGAN SECURITIES, INC.
022 B000001 13-3379014
022 C000001 7861
022 D000001 0
022 A000002 CITIGROUP GLOBAL MARKETS, INC.
022 B000002 11-2418191
022 C000002 7475
022 D000002 0
022 A000003 MORGAN KEEGAN & CO., INC.
022 B000003 64-0474907
022 C000003 4727
022 D000003 0
022 A000004 PERSHING LLC
022 B000004 13-2741729
022 C000004 4482
022 D000004 0
PAGE 4
022 A000005 OPPENHEIMER & CO., INC.
022 B000005 13-5657518
022 C000005 2793
022 D000005 0
022 A000006 MERRILL LYNCH, PIERCE, FENNER & SMITH
022 B000006 13-5674085
022 C000006 0
022 D000006 1360
022 A000007 BARCLAYS CAPITAL, INC.
022 B000007 61-0316560
022 C000007 0
022 D000007 559
022 A000008 SOCIETE GENERALE
022 B000008 00-0000000
022 C000008 537
022 D000008 0
022 C000009 0
022 D000009 0
022 C000010 0
022 D000010 0
023 C000000 27875
023 D000000 1919
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
PAGE 5
028 C030000 0
028 C040000 0
028 D010000 0
028 D020000 0
028 D030000 0
028 D040000 0
028 E010000 0
028 E020000 0
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
PAGE 6
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
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
PAGE 7
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 125.7
062 P000000 0.0
062 Q000000 0.0
062 R000000 0.0
063 A000000 0
063 B000000 8.3
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 N
070 K010000 Y
070 K020000 Y
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
PAGE 8
070 P020000 N
070 Q010000 N
070 Q020000 N
070 R010000 N
070 R020000 N
071 A000000 26148
071 B000000 16837
071 C000000 411582
071 D000000 4
072 A000000 6
072 B000000 14925
072 C000000 0
072 D000000 0
072 E000000 0
072 F000000 1291
072 G000000 103
072 H000000 0
072 I000000 14
072 J000000 4
072 K000000 0
072 L000000 17
072 M000000 7
072 N000000 12
072 O000000 0
072 P000000 0
072 Q000000 0
072 R000000 30
072 S000000 19
072 T000000 0
072 U000000 0
072 V000000 0
072 W000000 168
072 X000000 1665
072 Y000000 0
072 Z000000 13260
072AA000000 0
072BB000000 1107
072CC010000 14353
072CC020000 0
072DD010000 12831
072DD020000 0
072EE000000 0
073 A010000 0.5700
073 A020000 0.0000
073 B000000 0.0000
073 C000000 0.0000
074 A000000 5115
074 B000000 0
074 C000000 0
074 D000000 416787
074 E000000 0
PAGE 9
074 F000000 0
074 G000000 0
074 H000000 0
074 I000000 0
074 J000000 2191
074 K000000 0
074 L000000 8881
074 M000000 120
074 N000000 433094
074 O000000 0
074 P000000 234
074 Q000000 0
074 R010000 0
074 R020000 0
074 R030000 0
074 R040000 164
074 S000000 101004
074 T000000 331692
074 U010000 22531
074 U020000 0
074 V010000 14.72
074 V020000 0.00
074 W000000 0.0000
074 X000000 6600
074 Y000000 0
075 A000000 0
075 B000000 325842
076 000000 16.04
077 A000000 N
078 000000 N
080 C000000 0
081 B000000 0
082 B000000 0
083 B000000 0
084 B000000 0
SIGNATURE MARK BRADLEY
TITLE TREASURER