There are welcome centers at each of the seven sites where you can learn about available tours and programs, and get your passport books stamped. Please visit the "Directions" page below to get the other physical addresses.
The closest locations to purchase an interagency pass are:
Bombay Hook National Wildlife Refuge, Smyrna, DE
Prime Hook National Wildlife Refuge, Milton, DE
In addition, please refer to this link for locations across the country to purchase interagency passes.
There are seven sites throughout the state that collectively tell First State National Historical Park's story, and can be visited in any order. Currently, the park does not have one, central visitor center. However, each site has some type of welcome center where you will receive informaiton about the site and available tours.