Hex Kleinmartin
Google
Set right on the edge of the lower Niagara Gorge, this little gem of an art museum holds not only some great display space, but its own library.  With an art collection of around 1400 pieces, they're able to field themed exhibits in addition to the traveling or focus artist exhibits that they also host.  When we went, there was an exhibit focused on a First Nations beadwork artist, and another exhibit on Inuit artists. These were in addition to exhibits from the museum's own collection.
The building itself is beautiful, with lots of wood panelled rooms and hallways. The gallery space is on the first and second floors (with more artwork in hallway spaces and on the stairwell walls and landings), and the library is in the basement, with more sculptures on the shelves, and plenty of chairs and table spaces to read and do research with.
Being a not-for-profit, they ask for donations, and are able to take them electronically, if you want to do that.  They also have a nice little gift shop area with some pieces of art that are for sale, as well as some books, cards, and even maps for local walking tours of the nearby area.