This monument, about 1½ miles east-southeast of Oak near the Little Blue River, was erected on the Oregon Trail by Nuckolls County in memory of those killed in the raids of 1864. Oak Grove was a stage station from about 1856 and is usually identified as Pony Express station No. 7; on August 7, 1864, warriors attacked it and killed two men. Nuckolls County was organized here in 1871. Only the fenced monument area and its parking are open; the land around it is private.