From Halopedia, the Halo wiki
Esztergom Spaceport was a spaceport in the city of Esztergom on the planet Reach.
During the Fall of Reach Esztergom Spaceport was used to evacuate civilians from the planet. It was destroyed by the Covenant during the battle. By January 2610 it was used to send a package containing Dr. Halsey's personal journal to Earth.
Esztergom's Spaceport Stamp