My favorite bookstores in DC paired with a nearby coffee shop to make an outing of it! You'll find the bookstore listed first with its paired coffee shop listed below.
Map
I always find the best recommendations here
East City Bookshop
Cozy new spot on Barracks Row. Friendly staff and perfect drinks.
CIVIC. On Eighth
Bookstore featuring LGBTQ+ stories and authors
Little District Books
High quality coffee
Peregrine Espresso
Used bookstore, packed full of books and funny shelf notes.
Capitol Hill Books
Nice people watching spot on their patio in good weather
7th St. Hill Cafe
Bigger store with a nice kids section. They have their own coffee shop, but check-out my recommendation below as well.