In the modern farmlands of the Arkansas River Valley are the remains of a large group of ancient earthworks known as the Toltec Mounds. This impressive archeological site has attracted national interest for over 100 years and was designated a National Historic Landmark in 1978. Toltec Mounds is one of the largest and most complex sites in the Lower Mississippi Valley. Located on the bank of Mound Pond, it once had an earthen embankment on three sides. A century ago, 16 mounds were known inside the embankment and two of them were 38 to 50 feet high. Today, several mounds and a remnant of the embankment are visible and locations of other mounds are known.
The embankment was an impressive earthwork 8 to 10 feet high and 5,298 feet long
with a ditch on the outside. Mounds were placed along the edges of two open areas (plazas) which were used for political, religious, and social activities attended by people from the vicinity. Mound locations seem to have been planned using principles based on alignment with important solar positions and standardized units of measurement. Most of the mounds were square or rectangular, flat-topped platforms with buildings on them. Mound B (38'high) was constructed and enlarged over a long period of time with religious buildings on it. Mounds such as D,E,S, and G, were low platforms, apparently with houses on them. Mound C (12' high) was dome-shaped and constructed to cover burials. Native Americans also lived here in the 1400s, but they did not build the mounds.