Northwood Lake is a 653 acre water body located in Rockingham and Merrimack counties in central New Hampshire, United States, in the towns of Northwood and Epsom. The town of Deerfield occupies part of the southern shore. The outlet of the lake is the Little Suncook River, flowing west to the Suncook River, a tributary of the Merrimack River. The lake is classified as a warmwater fishery, with observed species including smallmouth and largemouth bass, chain pickerel, and brown bullhead, and white perch. Milfoil is present in the lake.