The Tropic of Cancer is at 23 degrees 27 minutes North. 90 degrees West Longitude is the meridian that passes through Memphis TN, New Orleans, LA, through El Salvador and into the Pacific. . 23 N 90 W is in the Gulf of Mexico, due South of New Orleans and about even with just north of Tampico Mexico. (By the way, “parallel” always refers to latitude; longitude is a meridian. 90 degree parallel is either the North or South Pole.) You can see in google maps by typing n latitude first, longitude second, as in 23N 90 W