The Don-2N radar (Russian: Дон-2Н, NATO: Pill Box) is a large missile defense and early warning active electronically scanned array radar outside Moscow, and a key part of the Russian A-135 anti-ballistic missile system designed for the defense of the capital against ballistic missiles.

Each of its four faces has an 18 m (59 ft) diameter Super high frequency band radar giving 360 degree coverage.

To the right of each circular search and track array, separated by a vertical structure for shielding, is a square antenna array (edge length 10 m) for guiding the interceptor missile by data link.

[2] It has a range of 3,700 km for targets the size of a typical ICBM warhead.

The 1998 SIOP targeted this radar facility with 69 consecutive nuclear weapons.