State Route 259 (SR 259) is an approximately 1.48-mile (2.38 km) state highway in the U.S. state of California, serving as a freeway connector between I-215 and SR 210 in San Bernardino.

SR 259 splits off from I-215 as a full freeway and continues north, interchanging with Highland Avenue.

[7] Since 2022, Caltrans had erected SR 259 reassurance markers just beyond the start of the entrance ramps from SR 210[8] and I-215.

[9] SR 259 is part of the California Freeway and Expressway System,[10] and is a freeway for its entire length,[2] and is part of the National Highway System,[11] a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.

Prior to its role as a state highway, the route followed by SR 259 formed a portion of the Santa Fe "Kite-Shaped Track" which looped throughout Southern California, including through communities of the eastern San Bernardino Valley.