These changes of control are shown in the flag display at the park's visitor's center.
Of course it was always a bit more than just a trading post, it also served a military function.
As a trading post it grew and from 1819-1821 it was the site of the first Arkansas territorial capital. Thus it was a bit of a town. Here is a well, that due to being so close to the river still has water in it.
There are also a few markers telling where some important buildings were during the territorial period. Of course some locations have been reclaimed by the Arkansas River.
It was also at Arkansas Post that the first Christian services were held in Arkansas. This picture also shows the bayou nearby. The Arkansas River used to flow there, now this is more of a backwater area.
Besides being interesting because of its significance in the history of Arkansas and frontier trading there was also a Civil War battle here in January 1863. In the fall of 1862 Union General John McClernand had received permission to raise a large force to take Vicksburg. He thought it would be an independent command but later maneuverings by US Grant and Henry Halleck left Grant in command along the Mississippi River. McClernand would end up with a corps, which is what he would have had if he hadn't made a secret arrangement to have an independent command created. But before Grant arrived to take command of McClernand's force he took the opportunity to attack Arkansas Post. McClernand convinced the navy to come along; which was imperative, otherwise the campaign would have likely gone nowhere. He also had Sherman's corps, in all around 33,000 men. The Confederates had about 5,000 at Arkansas Post, also protected by Fort Hindman.
The Union troops landed on January 9, the navy bombarded on the 10th and on the 11th the army and navy combined to attack the fort. The weight of numbers eventually secured the victory for the Union but not until nearly a 1,000 men were casualties. About 4,800 Confederates surrendered.
When Grant heard about the battle he was furious, thought it was a waste of time and men. But then he heard Sherman had supported the idea and his temper cooled. Was it necessary to take Fort Hindman to take Vicksburg? Probably not, but it did clear a Confederate base from his flanks. Also the capture represented about a fourth of all Confederates in Arkansas, which certainly helped the overall war effort some.
There are some earthworks preserved within the national park with a small walking trail that takes you out to an artillery piece.
Fort Hindman has been reclaimed by the Arkansas River. Here is a drawing of the fort.
I believe the park staffer in the visitor's center said the fort is likely where the tree is growing in the water in the left center of the picture. That might be right, or wrong, but is probably close if it is wrong.