Does anyone know where to find a dataset for US Boat Launches (both Fresh and Salt)? I have found several statewide results, but nothing on a national level. Does anyone know if this information is aggregated in a single location anywhere either as an open or paid dataset?
You can use the Overpass Turbo visual API to check out coverage of the tag, for example, this query (click "Run").
Check out this answer for downloading bulk OSM files, filtering for your specific tags, and converting to various GIS formats.