Complex sentence: The land has been continuously owned by the federal government since it was purchased from Mexico in 1848 as part of the Mexican Cession and the Bundy family has been using the federal land since 1877.
Split into simpler sentences: The land has been continuously owned by the federal government since it was purchased from Mexico in 1848 as part of the Mexican Cession. The Bundy family has been using the federal land since 1877.