Middlesex County accounts for 792 of Massachusetts’s 1,650 muskrat records, nearly half the state total. It’s the band of towns west and north of Boston, threaded by the Concord, Sudbury, and Mystic rivers, where slow brown water, cattail edges, and conservation land sit right beside busy trails. Worcester and Essex counties follow at a distance, and every mainland county has at least a few reports, though none come from Martha’s Vineyard or Nantucket.
Small wildlife areas, a big spring jump
The named places are modest state wildlife lands. Westborough Wildlife Management Area leads, with Burrage Pond Wildlife Management Area in Plymouth County’s old cranberry bogs and Bolton Flats in the Nashua River valley also appearing. Away from the wildlife areas, Brook Farm matches Burrage Pond with 8 records, and the Mystic Lakes, just north of Boston, add 2.
Reports rise about fivefold from February to March, peak in April at 428, then fall away through summer to an October low before a smaller climb into December. Muskrats don’t hibernate, so that early-winter uptick likely reflects animals moving around lodges and thin ice while bare banks make them easier to pick out. With 1,643 records from iNaturalist, the overall pattern leans toward places people already walk.
In Massachusetts it’s a native species with an S5, secure, NatureServe rank.
Full species profile
