In aviation, runway numbers represent the magnetic compass heading of the runway, rounded to the nearest 10 degrees and shortened to two digits. Therefore, Runway 23 indicates that the runway is oriented toward a magnetic heading of approximately 230 degrees (which is Southwest). If a pilot is landing on Runway 23, they are flying toward the Southwest. Because runways can be used in two directions, the opposite end of the same strip would be named Runway 05 (230° - 180° = 50°). If an airport has two parallel runways pointing in the same direction, they are designated with "L" and "R" for Left and Right (e.g., 23L and 23R). This naming convention is vital for safety, as it allows pilots to quickly align their instruments and ensures that both the cockpit and Air Traffic Control have a shared, numeric understanding of the aircraft's physical orientation relative to the earth's magnetic poles. In 2026, as the Earth's magnetic north slowly shifts, some airports may actually have to "renumber" their runways to stay within the 10-degree rounding rule.