Croton-on-Hudson is a small Westchester village where the Croton River meets the Hudson. It has the commuter ease of the lower Hudson Valley, but also enough old infrastructure, river parkland, and colonial history to reward a slow day.
The best visit links Van Cortlandt Manor, the Old Croton Aqueduct, and the open peninsula of Croton Point Park. Add nearby Croton Gorge Park if you want the full waterworks story.
It is not a grand destination, and that is part of the charm. Come by train, walk, eat something simple, and let the river and the aqueduct set the pace.