Anahuac is a small town opposite Tampico across the Pánuco River, in the state of Veracruz. Just like the little towns in Veracruz near Tampico, it's nothing special. It's however still worth going as it's the only way for you to see the river without going into the Old Customs House (museum).
You only need to walk to a corner to get a small boat (MXN$5) and you get to see the river, the port, the naval base, and the little town.