Canal Street really was a canal back in the early 19th century; it carried filthy water from polluted Collect Pond, near Lafayette Street, and emptied it into the Hudson.
After the canal was filled in and made a road in 1820, the far western edge of newly named Canal Street served a more ghoulish purpose.
“The Street took its name naturally from the little stream which was called a canal,” writes Charles Hemstreet in his 1899 book Nooks and Corners of Old New York.
“The locality at the foot of the street has received the local title of “Suicide Slip” because of the number of persons in recent years who have ended their lives by jumping into Hudson River at that point.”
The Historical Guide to the City of New York also marks this as a suicide spot. “The small park at West and Canal Streets was once called Suicide Slip,” it states mysteriously.