Ditches, moist fields, thickets, and wet open forests, often in disturbed sites. A North American native, though tirst collected in Michigan as recently as 1931 in Monroe and Wayne Cos. The disjunct Alcona Co. record is from the shore of Hubbard Lake, in 1950 (Hebert, s.n., ND).

This has clearly been increasing in recent years, and is now a relatively characteristic plant of sucessional meadows and woodland in southernmost Michigan. Carex frankii is unusual in retaining perigynia quite late in the season, even into late October.