Burnet County Texas map

The county sits on the northeastern rim of the Edwards Plateau, at the point where the plateau meets the Llano Uplift — the reason the geology changes from flat limestone to exposed granite and gneiss within a few miles as you drive west. Austin is 45 miles southeast in a straight line, Round Rock 37 miles, Georgetown 33 miles and Killeen 36 miles northeast.

Seven counties adjoin it: Lampasas north, Bell northeast, Williamson east, Travis southeast, Blanco south, Llano west and San Saba northwest. The Colorado River forms much of the Llano County line, drowned under Lake Buchanan and Lake LBJ for most of that distance.

The legislature created Burnet County in 1852 from parts of Bell, Travis and Williamson counties and organized it in 1854. It is named for David Gouverneur Burnet, the interim president of the Republic of Texas in 1836 — and, like the man, the name is said with the stress on the first syllable. The county's population was 49,130 in 2020 and the Census Bureau estimated about 55,722 by 2024, making it one of the faster-growing rural counties in Central Texas.

Marble Falls is the larger town and the commercial centre, on US-281 where it crosses Lake Marble Falls; Burnet, 13 miles north, is the seat and has the courthouse square. Most of the smaller cities on this list — Granite Shoals, Meadowlakes, Cottonwood Shores, Highland Haven, Double Horn and the Burnet County part of Horseshoe Bay — are lakeside subdivisions that incorporated to control their own development. Horseshoe Bay straddles the line and has most of its population in Llano County. Bertram, on SH-29 toward Georgetown, is the one town on the eastern prairie side rather than the lakes.

The Lower Colorado River Authority built the chain to control the floods that used to run down the Colorado and to generate power. Buchanan, completed in 1937, is the largest and the only one of the four that is drawn down heavily in drought — the lower three are held at near-constant level, which is what made lakeside subdivision possible. Lake LBJ was called Granite Shoals Lake until it was renamed in the 1960s for the president who had done most to get the dams funded as a young congressman.

Inks Lake State Park, on Park Road 4, is built on the pink Valley Spring gneiss and Town Mountain granite of the Llano Uplift, with swimming off the rock, a nine-hole course and cabins. The falls that gave Marble Falls its name were natural rapids over the same rock; they went under water when Max Starcke Dam impounded Lake Marble Falls in the early 1950s, and are visible only in the rare years the lake is drawn down for maintenance.

Granite Mountain rises just west of Marble Falls, a solid dome of pink Town Mountain granite. In the 1880s its owners offered the stone free to the state for the new Capitol in Austin, in exchange for convict labour to quarry it and a railroad spur to move it, and the building's exterior is that granite. The quarry is still in production and the same stone appears in buildings across the country. Despite the name, there is no marble in the county; the rock is igneous, part of a batholith that also surfaces to the west at Enchanted Rock, over the Llano and Gillespie county lines.

Longhorn Cavern State Park, on Park Road 4 south of Burnet, is a cave of a different type from most Texas show caves: it was cut by an underground river dissolving and scouring limestone, so its passages are smooth, wide corridors rather than chambers full of dripstone. The Civilian Conservation Corps cleared and lit it in the 1930s and built the observation tower and administration building above it. Tours are guided, and the temperature underground stays near 68 degrees year round.