According to the
United States Census Bureau, the township has a total area of , of which is land and , or 0.31%, is water.
Communities •
Chatham is a village at the junction of
M-67 and
M-94. •
Eben Junction is an
unincorporated community at . The Eben Junction
ZIP code 49825 provides P.O. box service for a portion of Rock River Township and an area of adjacent
Onota Township. It was a station at the junction of the
Minneapolis, St. Paul and Sault Ste. Marie Railroad and the
Munising Railway. A post office was established on August 1, 1908, with Emil Hoppe as the first postmaster of the Finnish settlement. It was named for Mr. Rumely, who settled here from
Ohio about 1873. It was a station on the Munising Railway about 1890. A post office was established on September 24, 1906, with Cyrill Valind as its first postmaster. The office closed on March 31, 1943, and was reestablished on December 16, 1947. It closed again on August 31, 1959, and is now a
CPO of Eben Junction providing P.O. box service for
ZIP code 49826. The Post Office was located in the old Rumely Store, but closed in 2011 or 2012 when the store closed. The store reopened, under new ownership, in February 2015, but without any mail service. •
Slapneck is a place at . •
Sundell is an unincorporated community at . In 1908,
Dorsey was a station on the
Munising, Marquette and Southeastern Railway. The first postmaster, Selma Harsila, submitted her maiden name, Sundell (
Swedish), as the name of the new post office. The office operated from August 31, 1922 until August 25, 1967. Dorsey is approximately a half mile to the west at . •
Winters was a former post office in the township at . The settlement was named for John D. Winters, who was also the first postmaster. The post office first opened September 20, 1889 and closed August 15, 1923. It reopened from February 25, 1924, until June 15, 1928. ==Demographics==