A small AZA-accredited zoo inside Brandywine Park, under five acres, run by Delaware State Parks. Wheelchair and stroller accessible throughout, free parking across the road, and free to walk into from December through February.
Restrooms
Gift shop
Accessibility noted
Parking noted
This one is outdoors. It's in this section because it has a gate, a ticket and closing time, not because it keeps the rain off.
Delaware Division of Parks and Recreation, with the Delaware Zoological Society→
OpenTrails and grounds Daily, sunrise to sunset · Visitor center, Monday – Friday 9am – 4pm (April to October) · Visitor center, Saturday & Sunday 10am – 3pm (April to October)
The visitor center hours above are the April-to-October ones. What it does in winter is not published.
Four miles of trails through forest, meadow and along the Red Clay Creek, free and open sunrise to sunset, with a creek shallow enough for children to stand in and a dog welcome on a leash. This is an outdoor trip: the building is small.
Free
Restrooms
Gift shop
Accessibility noted
Parking noted
NOT a wet-weather answer. The ranger station is worth a look and will hold a child for about ten minutes; everything else here is outside.
Delaware Nature Society→
Why these are separate from the parks
A park is just open — you turn up. These are structured places to spend a few hours: zoos, nature centers and other destinations with posted hours, visitor facilities or a defined program. Not all of them charge — Ashland's grounds and trails are free — but all of them have a schedule worth checking before you leave, which is why they sit apart from the parks with the hours and the price up front.
Know someone who'd find this useful? Send it their way. It might save them a wasted trip, give a dog somewhere to run, or help keep the kids busy when it rains.