Complex sentence: The 1825 survey states that the lands extend to about 21,000 acres, and such was the importance of the estate that a railway station was built for it, presumably as much for agricultural use as personal.
Split into simpler sentences: The 1825 survey states that the lands extend to about 21,000 acres. Such was the importance of the estate that a railway station was built for it, presumably as much for agricultural use as personal.