From 1905 through 1910, the Vilas family donated an additional $42,000 for improvements, and public donations of $10,000 were raised for the enlargement and improvement of the park. The park was named in memory of the Vilas' son, Henry, who died at a young age due to complications from diabetes. In 1911, the first animal exhibits were created, representing the start of the Henry Vilas Zoo.

In what has proved to be a defining and truly visionary move, the Vilas Family stipulated that the park always be admission free. As the zoo developed within the park, it too remained free. Today it's an extraordinary asset that few communities our size can claim. Indeed, our Zoo is one of only a few, no-admission, free parking AZA accredited zoos nationwide.

In 1983, the Zoo was identified as a regional community that could be better served by county operations. The zoo (approximately 28 acres) was "separated" from the city-owned park (about 50 acres), and a County Zoo Commission was formed. Dane County now operates the zoo, contributing 80 percent of the operating funds while the City of Madison contributes 20 percent.