In New York, hundreds of thousands of revelers lined the St. Patrick's Day parade route, cheering the marching bands, dance troupes and politicians.
In downtown Chicago, thousands along the Chicago River cheered as workers on a boat dumped dye into the water, turning it a bright fluorescent green for at least a few hours in an eye-catching local custom.
And in Ireland, Dublin's five-day St. Patrick's Day festival was unfolding with a new addition. For the first time, up to 8,000 visitors from around the world were due to march in a so-called people's parade Sunday, when Ireland's capital city also intends hold its usual procession of bands and pageantry.
Here are some photos of St. Pat's celebrations around the country.