The Franklin Mountains of Texas () are a small range long, wide that extend from El Paso, Texas north into New Mexico. The Franklins were formed due to crustal extension related to the Cenozoic Rio Grande rift. Although the present topography of the range and adjoining basins is controlled by extension during rifting in the last 10 million years, faults within the range also record deformation during the Laramide orogeny, between 85 and 45 million years ago. The highest peak is North Franklin Peak at . Much of the range is part of the Franklin Mountains State Park. The mountains are composed primarily of sedimentary rock with some igneous intrusions. Geologists refer to them as tilted-block fault mountains and in them can be found 1.25 billion-year-old Precambrian rocks, the oldest in Texas. Gallery See also Beach Mountains Chihuahuan Desert Davis Mountains Guadalupe Mountains McKittrick Canyon Trans-Pecos References External links Mountain ranges of New Mexico Mountain ranges of Doña Ana County, New Mexico Mountain ranges of Texas Mountain ranges of El Paso County, Texas Geography of El Paso, Texas