The Grand River winds northward along the western boundary of the county and the Red Cedar River flows west across the northern section into the Grand River in Lansing. Most of the midsection of the county drains to the north into the Red Cedar River and the northern tier of townships drain to the south into the Cedar. The Sycamore Creek, flowing northwest into the Red Cedar in Lansing, drains much of the midsection of the county. Most of the southern portion of the county drains south or west into the Grand River. The southeastern corner drains to the southeast into the Huron River via the Portage Creek and Portage River and a series of small lakes.