Not very far. Penn Station is between 7th and 8th Avenues, from approximately West 33rd to West 34th, and Grand Central Station is at 42nd and Lexington. Approximately 17 to 20 street blocks (north/south) blocks equals a mile, and approximately 3 to 4 avenue blocks (east/west blocks) equals a mile. So the distance between the two stations is about one and a half miles.
Less than 2 miles as the crow flies (meaning, if you were to draw an imaginary straight line between them on the map).
Brooklyn is about one and two-thirds to one and three-quarter miles almost straight east (but slightly, slightly southeast) from the northeast corner of Penn Station (34th Street and 7th Avenue).
In road miles, the distance is only slightly longer; two to two and a quarter miles. It's almost a straight shot across town: you'd drive two blocks north, from West 34th to West 36th, then make a left and drive east across Manhattan to the East River, through the Queens-Midtown Tunnel, which brings you out in Queens, on the north side of Maspeth Creek. Brooklyn is on the south side, a mere moment's drive away.
This question is too vague to be answered. Brooklyn is almost 100 square miles in area, and 8 of New York City's 9 subway lines (not including the shuttles) run through it. The directions will be completely different, depending on where in Brooklyn you are going.
Please ask your question again, this time specifying an address in Brooklyn, or at the very least, a neighborhood.
There is roughly one mile, or a little less, between Penn Station and the Rockefeller Center Station.
One mile is equal to 17 to 20 street blocks, or 5 to 10 avenue blocks (the length of the avenue blocks varies considerably, depending on the neighborhood you're in).
Penn Station is at 34th Street, between 8th and 7th Avenues, and the Rockefeller Center Station is on 47th through 50th Street, at 6th Avenue. So it's 13 to 16 street blocks and 1 avenue block from 34th Street-Penn Station to the 47th-50th Street-Rockefeller Center Station.
Penn Station is at 33rd to 34th Streets, between 8th and 7th Avenues. So it's 7 to 8 blocks from 40th Street. That's a little over 1/3 of a mile (0.53 km).
It's 5 blocks down from the east side of Penn Station. Penn Station is at 33rd to 34th Streets, between 8th and 7th Avenues.
Penn Station is at 34th Street so it is 20 blocks away from 54th St. You would take the subway two stops north.
It's 8 blocks straight north from Penn Station (34th Street between 8th and 7th Avenues) to the Port Authority Bus Terminal (42nd Street at 8th Avenue).
It's almost exactly half a mile straight uptown (plus half a block's walk east or west, depending on whether you exit Penn Station at 8th or 7th Avenues). The Shubert Theatre is at 225 West 44th Street, between 8th and 7th Avenues, and Penn Station is at 33rd to 34th Street between 8th and 7th Avenues.
It's about two and two-thirds to two and three-quarter miles pretty much straight Downtown.
Penn Station is 13 blocks directly Downtown from 47th and 7th. Penn Station is between 7th and 8th Avenue, from West 33rd to West 34th Street. The west entrance/exit is at 8th Avenue, and the east entrance/exit is on 7th Avenue. So, you exit Penn Station and walk 13 blocks Uptown. If you exit onto 8th Avenue, then you will need to walk one block east and 13 blocks Uptown.
By train, its about 25 minutes
300 miles
It's about 2.5 miles (4 km) as the crow flies, from the intersection of 40th Street and 5th Avenue to the intersection of Canal Street and 6th Avenue.
There are several Penn Stations located in the US but the most famous is by far Pennsylvania Station (known as Penn Station) in New York City, New York. See Related Links for more information about the station.
It's about 7 miles from Penn Station in Chelsea to 1 Police Plaza in lower Manhattan.
29 miles