Spain had a difficult time controlling the vast territory of Florida, and, unable to stop the influx of American settlers, finally ceded the area to the United States in 1821. Originally part of the Arredondo Grant, Alachua County was created in 1824 as a massive county, extending from the Georgia border to Tampa Bay. Constant partitioning and the Second Seminole War slowed the county's development, but the coming of the Florida Railroad opened up the interior for both settlement and trading.