Agate, NebraskaAgate is in Sioux [County, Nebraska|Sioux County], Nebraska, United States. Agate is located on Nebraska Highway 29, south-southeast of Harrison. It is home to Agate [Fossil Beds National Monument].HistoryA post office was established at Agate in 1899, and remained in operation until it was discontinued in 1968. Agate was named for James H. Cook's Agate Springs Ranch, which was in turn named for the agate deposits in the area.ClimateAccording to the Köppen Climate Classification system, Agate has a semi-arid climate#Cold [semi-arid climates|cool semi-arid climate], abbreviated BSk on climate maps.