At what altitude does coordination occur for aircraft departing from areas close to the ARTCC boundary?

Coordination for aircraft departing from areas close to the ARTCC (Air Route Traffic Control Center) boundary is essential for maintaining safe air traffic operations as they transition between different control centers. In this context, the coordination typically occurs below 5,000 feet. This is because lower altitudes are often used for departures and arrivals, where quick communication and coordination can mitigate the risks of potential airspace conflicts as aircraft are maneuvering to enter or exit controlled airspace. By ensuring that coordination happens below this altitude, controllers can allow for more effective management of aircraft as they approach the boundary, facilitating a smoother transition between various sectors or ARTCCs.