Additionally, Rapid City was experiencing a population boom due to the establishment of nearby Ellsworth Air Force Base.

The Federal Emergency Relief Administration sponsored the construction of Skyline Drive, which would provide access to the park.

Due to a dispute between Sullivan and the WPA over the dinosaur teeth—Sullivan retired from the project in 1937 and the new foreman disagreed with him over the installation method for the T. Rex sculpture's teeth—construction was not finished until 1938.

Additionally, fossilized dinosaur footprints that had been found in the area were planned to be moved to the park, but this apparently was never completed.

The city refurbished the sculptures, walkways, and landscaping, and added a larger parking lot and a new concession and gift shop.

With the exception of the Protoceratops, the selected dinosaurs were based on fossils found in South Dakota and the Western United States.

[3] The dinosaurs were constructed out of 2-inch-wide (5.1 cm) black iron pipe under a wire mesh frame and a concrete skin.

[4] This includes dragging tails; three fingers on the T. rex as opposed to two; the dimensions; and the naming of the E. annectens sculpture as the now-outdated classification Trachodon.