| Table ID No. | MCAG | Legal Name | Entity Name | Government Description |
| 1667 | 1726 | Port of Mabana | Mabana, Port of | Port District (Includes Airports) |
| 1925 | 2110 | Mabton School District No. 120 | Mabton School District No 120 | School Districts |
| 357 | 0839 | City of Mabton | Mabton, City of | City/Town |
| 2267 | 0634 | Maggie Lake Water District | Maggie Lake Water District | Water/Sewer District |
| 2268 | 1157 | Malaga Water District | Malaga Water District | Water/Sewer District |
| 358 | 0814 | Town of Malden | Malden, Town of | City/Town |
| 2269 | 2277 | Manchester Water District | Manchester Water District | Water/Sewer District |
| 1668 | 1737 | Port of Manchester | Manchester, Port of | Port District (Includes Airports) |
| 1926 | 1858 | Mansfield School District No. 207 | Mansfield School District No 207 | School Districts |
| 359 | 0278 | Town of Mansfield | Mansfield, Town of | City/Town |
| 1589 | 1683 | Manson Park and Recreation District | Manson Park and Recreation District | Park and Recreation District |
| 1927 | 1822 | Manson School District No. 19 | Manson School District No 19 | School Districts |
| 360 | 1177 | City of Maple Valley | Maple Valley, City of | City/Town |
| 361 | 0740 | Town of Marcus | Marcus, Town of | City/Town |
| 66 | S408 | Marine Employees Commission | Marine Employees Commission | Agency, Commission, or Board |
| 1257 | 1430 | Marshland Flood Control District | Marshland Flood Control District | Flood Control District |
| 1548 | 2752 | Martin Hall Juvenile Facility | Martin Hall Juvenile Facility | Miscellaneous |
| 1928 | 1971 | Mary M. Knight School District No. 311 | Mary M Knight School District No 311 | School Districts |
| 1929 | 2063 | Mary Walker School District No. 207 | Mary Walker School District No 207 | School Districts |
| 1041 | 2583 | Marysville Fire District | Marysville Fire District | Fire Protection District |
| 1930 | 2031 | Marysville School District No. 25 | Marysville School District No 25 | School Districts |
| 362 | 0682 | City of Marysville | Marysville, City of | City/Town |
| 581 | 2412 | Mason Conservation District | Mason Conservation District | Conservation District |
| 638 | 0144 | Mason County | Mason County | County |
| 172 | 0052 | Mason County Cemetery District No. 1 | Mason County Cemetery District No 1 | Cemetery District |
| 1042 | 1223 | Mason County Fire Protection District No. 1 | Mason County Fire Protection Disrict No 1 | Fire Protection District |
| 1043 | 1231 | Mason County Fire Protection District No. 11 | Mason County Fire Protection District No 11 | Fire Protection District |
| 1044 | 1232 | Mason County Fire Protection District No. 12 | Mason County Fire Protection District No 12 | Fire Protection District |
| 1045 | 1233 | Mason County Fire Protection District No. 13 | Mason County Fire Protection District No 13 | Fire Protection District |
| 1046 | 2554 | Mason County Fire Protection District No. 16 | Mason County Fire Protection District No 16 | Fire Protection District |
| 1047 | 0298 | Mason County Fire Protection District No. 17 | Mason County Fire Protection District No 17 | Fire Protection District |
| 1048 | 0300 | Mason County Fire Protection District No. 18 | Mason County Fire Protection District No 18 | Fire Protection District |
| 1049 | 1224 | Mason County Fire Protection District No. 2 | Mason County Fire Protection District No 2 | Fire Protection District |
| 1050 | 1225 | Mason County Fire Protection District No. 3 | Mason County Fire Protection District No 3 | Fire Protection District |
| 1051 | 1226 | Mason County Fire Protection District No. 4 | Mason County Fire Protection District No 4 | Fire Protection District |
| 1052 | 1227 | Mason County Fire Protection District No. 5 | Mason County Fire Protection District No 5 | Fire Protection District |
| 1053 | 1228 | Mason County Fire Protection District No. 6 | Mason County Fire Protection District No 6 | Fire Protection District |
| 1054 | 1229 | Mason County Fire Protection District No. 8 | Mason County Fire Protection District No 8 | Fire Protection District |
| 1055 | 1230 | Mason County Fire Protection District No. 9 | Mason County Fire Protection District No 9 | Fire Protection District |
| 1360 | 0348 | Housing Authority of Mason County | Mason County Housing Authority | Housing Authority |
| 1321 | 1480 | Mason County Public Hospital District No. 1 | Mason County Public Hospital District No 1 | Hospital District |
| 2107 | 0674 | Mason County Public Transportation Benefit Authority | Mason County Public Transportation Benefit Authority | Transit/Transportation Authority |
| 1771 | 1789 | Mason County Public Utility District No. 1 | Mason County Public Utility District No 1 | Public Utility District (PUD) |
| 1772 | 1791 | Public Utility District No. 3 of Mason County | Mason County Public Utility District No 3 | Public Utility District (PUD) |
| 2142 | 2810 | Mason County Water Conservation Board | Mason County Water Conservation Board | Water Conservation Board |
| 363 | 0316 | Town of Mattawa | Mattawa, Town of | City/Town |
| 1931 | 1885 | McCleary School District No. 65 | McCleary School District No 65 | School Districts |
| 364 | 0344 | City of McCleary | McCleary, City of | City/Town |
| 2270 | 2299 | McKenna Water District | McKenna Water District | Water/Sewer District |
| 1932 | 2045 | Mead School District No. 354 | Mead School District No 354 | School Districts |
| 1933 | 2044 | Medical Lake School District No. 326 | Medical Lake School District No 326 | School Districts |
| 365 | 0716 | City of Medical Lake | Medical Lake, City of | City/Town |
| 366 | 0411 | City of Medina | Medina, City of | City/Town |
| 1934 | 1908 | Mercer Island School District No. 400 | Mercer Island School District No 400 | School Districts |
| 367 | 0413 | City of Mercer Island | Mercer Island, City of | City/Town |
| 1935 | 2087 | Meridian School District No. 505 | Meridian School District No 505 | School Districts |
| 368 | 0290 | Town of Mesa | Mesa, Town of | City/Town |
| 369 | 0562 | Town of Metaline Falls | Metaline Falls, Town of | City/Town |
| 370 | 0560 | Town of Metaline | Metaline, Town of | City/Town |
| 1447 | 1584 | Methow Okanogan Irrigation District | Methow Okanogan Irrigation District | Irrigation and Reclamation District |
| 1448 | 1585 | Methow Valley Irrigation District | Methow Valley Irrigation District | Irrigation and Reclamation District |
| 843 | 1016 | Methow Valley Rural Emergency Management Services | Methow Valley Rural Emergency Management Services | Emergency Management Services |
| 1936 | 1981 | Methow Valley School District No. 350 | Methow Valley School District No 350 | School Districts |
| 1549 | 1659 | Metro Municipal Corporation Snohomish County | Metro Municipal Corporation Snohomish County | Miscellaneous |
| 1590 | 2789 | Metro Park Dist of the City of Pullman | Metro Park Dist of the City of Pullman | Park and Recreation District |
| 1550 | 0828 | Metro-Local Narcotics Control Program | Metro-Local Narcotics Control Program | Miscellaneous |
| 1591 | 1660 | Metropolitan Park District of Tacoma | Metropolitan Park District of Tacoma | Park and Recreation District |
| 1517 | 1638 | Mid-Columbia Library | Mid-Columbia Library | Library District |
| 1551 | 0983 | Mid-Columbia Youth Consortium | Mid-Columbia Youth Consortium | Miscellaneous |
| 2271 | 2133 | Midway Sewer District | Midway Sewer District | Water/Sewer District |
| 67 | S245 | Military Department | Military Department | Agency, Commission, or Board |
| 1937 | 2024 | Mill A School District No. 31 | Mill A School District No 31 | School Districts |
| 371 | 0497 | City of Mill Creek | Mill Creek, City of | City/Town |
| 1449 | 1551 | Millerdale Irrigation District | Millerdale Irrigation District | Irrigation and Reclamation District |
| 372 | 0718 | Town of Millwood | Millwood, Town of | City/Town |
| 373 | 0590 | City of Milton | Milton, City of | City/Town |
| 68 | S147 | Office of Minority and Women's Business Enterprises | Minority and Womens Business Enterprise | Agency, Commission, or Board |
| 519 | S528 | Washington State Mint Commission | Mint Commission, Washington State | Commodity Commissions |
| 1450 | 1601 | Moab Irrigation District No. 20 | Moab Irrigation District no 20 | Irrigation and Reclamation District |
| 1451 | 1599 | Model Irrigation District No. 18 | Model Irrigation District No 18 | Irrigation and Reclamation District |
| 1938 | 2033 | Monroe School District No. 103 | Monroe School District No 103 | School Districts |
| 374 | 0685 | City of Monroe | Monroe, City of | City/Town |
| 1939 | 1886 | Montesano School District No. 66 | Montesano School District No 66 | School Districts |
| 375 | 0347 | City of Montesano | Montesano, City of | City/Town |
| 1940 | 1951 | Morton School District No. 214 | Morton School District No 214 | School Districts |
| 376 | 0490 | City of Morton | Morton, City of | City/Town |
| 582 | 2399 | Moses Lake Conservation District | Moses Lake Conservation District | Conservation District |
| 1452 | 1574 | Moses Lake Irrigation and Rehabilitation District | Moses Lake Irrigation and Rehabilitation District | Irrigation and Reclamation District |
| 1552 | 0559 | Port of Moses Lake Public Corporation | Moses Lake Public Corporation, Port of | Miscellaneous |
| 1941 | 1878 | Moses Lake School District No. 161 | Moses Lake School District No 161 | School Districts |
| 377 | 0318 | City of Moses Lake | Moses Lake, City of | City/Town |
| 1942 | 1949 | Mossyrock School District No. 206 | Mossyrock School District No 206 | School Districts |
| 378 | 0492 | City of Mossyrock | Mossyrock, City of | City/Town |
| 1943 | 2118 | Mount Adams School District No. 209 | Mount Adams School District No 209 | School Districts |
| 1944 | 2089 | Mount Baker School District No. 507 | Mount Baker School District No 507 | School Districts |
| 1945 | 2023 | Mount Pleasant School District No. 29-93 | Mount Pleasant School District No 29-93 | School Districts |
| 1946 | 2020 | Mount Vernon School District No. 320 | Mount Vernon School District No 320 | School Districts |
| 379 | 0644 | City of Mount Vernon | Mount Vernon, City of | City/Town |
| 380 | 0687 | City of Mountlake Terrace | Mountlake Terrace, City of | City/Town |
| 381 | 0840 | City of Moxee | Moxee, City of | City/Town |
| 1453 | 1607 | Mud Creek Irrigation District No. 7 | Mud Creek Irrigation District No 7 | Irrigation and Reclamation District |
| 1947 | 2028 | Mukilteo School District No. 6 | Mukilteo School District No 6 | School Districts |
| 2272 | 2461 | Mukilteo Water District | Mukilteo Water District | Water/Sewer District |
| 382 | 0690 | City of Mukilteo | Mukilteo, City of | City/Town |
| 69 | S144 | Municipal Research Council | Municipal Research Council | Agency, Commission, or Board |
| 1723 | 0785 | Museum Development Authority of Seattle | Museum Development Authority of Seattle | Public Development Authority |
