Good for

Somewhere dry when it rains

Delaware's indoor options are museums, historic sites and public libraries. Most of them shut two or three days a week, which is the part that wastes the drive.

Hours are the first thing to check and the first thing to go stale. Each entry carries the day I last read them off the operator.

12 places on this list

New Castle County

Delaware Art Museum
Museum · Wilmington
Delaware Museum of Nature & Science
Nature center · Wilmington
Hagley Museum and Library
Museum · Wilmington
New Castle County Libraries
Library · Wilmington
New Castle Court House Museum
Museum · New Castle
Winterthur Museum, Garden & Library
Museum · Winterthur

Kent County

Biggs Museum of American Art
Museum · Dover
Johnson Victrola Museum
Museum · Dover
Kent County Libraries
Library · Dover
The Old State House
Museum · Dover

Sussex County

Sussex County Libraries
Library · Georgetown
Zwaanendael Museum
Museum · Lewes

Other things to look for

A playground with a bathroom — Delaware Playgrounds With Restrooms
Go somewhere without buying a ticket — Free Things to Do in Delaware
Actually open on Sunday — Things to Do in Delaware on Sunday
Somewhere that works with a small child — Things to Do in Delaware With Toddlers
Shade in August — Delaware Parks With Shade
A drink where the dog can come — Dog-Friendly Breweries & Wineries in Delaware

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.