What is 'wide-open-spaces' about Post 58 in Arkansas?

According to the post's page on the Centennial Celebration site, Post 58's facility covers two states: "Texas 25 and Arkansas 58 ... one post home, two posts."

Post 58 is located in the Arkansas portion of the city of Texarkana; the other half of the city is in Texas. The posts started independently; both received their temporary charters in 1919. The joining occurred in 1923, and a new constitution was drawn up for the "Texarkana American Legion Post of Texarkana, Arkansas-Texas." Josh Morris was the first commander of the united post.

The post isn't the only straddler in Texarkana - the local federal building, which houses district courts for both states and the local post office, is built right on the state line with parts in both states and is the only federal office building in the United States to do so.