This addition increased the land area of what was already the largest state in the Union at the time (about 66,500 square miles (172,000 km2) to Virginia's 65,000 square miles, which then included West Virginia). The acquisition challenged the Missouri Compromise of 1820 by expanding slavery into free territory north of the southern Missouri border with Arkansas (Parallel 36°30′ north) as well as the Indian Removal Act by which tribes had just been moved west of the Missouri border 'permanently' as part of the forced Indian removal policy of ethnic cleansing.