Glenwood was first incorporated as a town on February 14, 1867 from Glenwood Plantation, which was organized for election purposes in 1863. After only a year, it surrendered its status as a town from 1868 to the early part of 1877, becoming formally organized as a plantation on March 5, 1877.
Glenwood Plantation includes most of Wytopitlock Lake and Orcutt Brook, which empties into it. The primary road is one that links United States Route 2-A in its southeast corner to United States Route 2 in Silver Ridge Township eight miles to the west.