Keywords: usgs science historical north dakota northdakota south dakota southdakota sylvanlake history geology statehood blackandwhite monochrome outdoor black and white This day in 1889, North Dakota and South Dakota became the 39th and 40th U.S. states (in that order). This historical photo of Sylvan Lake in Custer County, South Dakota shows characteristic erosion forms in the massive granite structures next to Sylvan Lake Lodge. In the distance is Harney Peak. This day in 1889, North Dakota and South Dakota became the 39th and 40th U.S. states (in that order). This historical photo of Sylvan Lake in Custer County, South Dakota shows characteristic erosion forms in the massive granite structures next to Sylvan Lake Lodge. In the distance is Harney Peak. |