The Rum River bends between the towns of Cambridge and Princeton and lands in the unincorporated community of Spencer Brook, in Isanti County.

The town itself was settled in the late 1850s by newcomers, many Civil War veterans, coming from the east coast. Spencer Brook includes the historic country school and was named after Benjamin Nicholson Spencer, a Judge, carpenter, and farmer, who came came to Minnesota in 1854 and was Alderman of the 1st Ward of Spencer Brook Township.

As for the Rum River than runs through it; the 1825 First Treaty of Prairie du Chien, was signed by William Clark and Lewis Cass (the famed Lewis and Clark) for the United States along with representatives of the Sioux, Sac and Fox, Menominee, Ioway, Winnebago and the Anishinaabeg tribes. This natural diversion channel (pictured) known as “Choking Creek”, became a treaty boundary separating the Dakota from the Ojibwe.

The Treaty tried to eliminate hostilities until separate treaties could be negotiated with individual tribes. This led to the Second, Third and Fourth Treaties of Prairie du Chien, whereby the Council of Three Fires, Ho-Chunk and the Sac and Fox, Sioux, Omaha, Iowa, Otoe and Missouria ceded territory to the United States.