Let Rosslyn be our guide. (Mike DeBonis/The Washington Post)

Gray (D) is mostly hoping for modest increases in downtown heights, but Rep. Darrell Issa (R-Calif.), powerful chairman of the House Oversight and Government Reform Committee, is also exploring whether to allow even taller buildings outside of the downtown area.

But where? What parts of our fair city are far enough away from our national treasures that we might tolerate buildings taller than the current limit of 130 feet?

There are, of course, already tall buildings mere miles from our national treasures. Rosslyn’s 300-foot-plus skyscrapers sit about a mile from the Lincoln Memorial and less than two miles from the Washington Monument.

Check out the map above (bigger version) to see what parts of the District would be off limits to tall buildings using the “Rossyln rule” — that is, assuming the proximity of Rosslyn’s moderately tall buildings is tolerable, where might similar structures be located inside the District yet no closer to various national landmarks than Rosslyn’s soon-to-be-tallest building?

If the White House is your touchstone, Rosslyn-type buildings could be located in places such as Buzzard Point and the Capital Riverfront/Ballpark Area. The New York Avenue and Rhode Island Avenue corridors would also be in play, not to mention North Capitol Street north of Rhode Island and Georgia Avenue north of Howard University.

Draw the circle around the Washington Monument, and Buzzard Point and the ballpark area are out of play, but the Poplar Point site just across the Anacostia River would still be a possibility.

Using the Capitol as the key landmark creates a much larger zone of exclusion, though much of upper Northwest Washington, as well as the city’s eastern and southern corners, would still be outside the low-building zone.