Summit Township is one of seventeen townships in Adair County, Iowa, USA. At the 2010 census, its population was 967.
Summit Township was organized in 1871. Summit is named from the ridge it contains that forms the watershed between the Mississippi and Missouri rivers.
A post office named Linwood opened in March 1895. Henry L. Manion was the postmaster. This post office was in Summit Township and was discontinued in 1903.
Summit Township covers an area of and contains one incorporated settlement, Adair. According to the USGS, it contains two cemeteries: Saint Johns and Sunny Hill.