Inks Lake, Texas

Park Road 4 is a scenic corridor in Burnet County that connects the constant-level waters of Inks Lake State Park with the underground limestone passages of Longhorn Cavern State Park. It is not a town, but rather a state parkway built by the Civilian Conservation Corps in the 1930s. The road winds through the Llano Uplift, crossing the geological boundary between the Precambrian granite core and the surrounding Cretaceous limestone. Along the way, it passes through Hoover's Valley, an area settled in the 1850s that now supports several Hill Country vineyards. The corridor functions as a single destination — a half-day or full-day drive with two state parks, a swimming hole, and a wine trail.

What It's Known For

The corridor is defined by its geology: the pink gneiss and granite outcroppings around Inks Lake, the dark gray limestone of Backbone Ridge, and the subterranean river-carved passages of Longhorn Cavern. It is also known for Devil's Waterhole, a deep pool surrounded by cliff faces that is one of the most popular swimming destinations in the Texas Hill Country.

History and Heritage: The CCC and Company 854

The area's modern infrastructure is a direct result of New Deal programs. Between 1934 and 1938, Civilian Conservation Corps Company 854 — composed primarily of young men from East Texas — was stationed in the area and assigned to develop both the cavern and the road connecting it to the surrounding parks. The company cleared the passages of Longhorn Cavern by hand, removing tons of accumulated debris, bat guano, and rock fall. They built the cavern's entrance structure, observation tower, and concession building using locally quarried limestone, fitting the stones without mortar in a style that remains structurally sound nearly ninety years later.

Company 854 also constructed Park Road 4 itself, cutting the roadbed through granite and limestone using hand tools, dynamite, and mule-drawn equipment. The road's stone culverts, retaining walls, and guardrails are original CCC work, built from the same materials excavated during construction. The craftsmanship is visible in the fitted stonework that lines the road at key curves and drainage points.

The Lower Colorado River Authority completed Roy Inks Dam in 1938, creating Inks Lake as a small, constant-level reservoir between Lake Buchanan and Lake LBJ. The dam is named for Roy Inks, a member of the first LCRA board of directors. The state acquired the land for Inks Lake State Park in 1940, and it officially opened to the public in 1950. Longhorn Cavern State Park opened earlier, in 1932, and was designated a National Natural Landmark in 1971.

Inks Lake and Devil's Waterhole

Inks Lake covers 831 acres and is maintained at a near-constant elevation of 888 feet above mean sea level. Because it is a run-of-the-river lake — water flows in from Lake Buchanan and out to Lake LBJ continuously — it rarely fluctuates more than a foot per year. This makes it the most reliable location for paddling and swimming in the Highland Lakes, even during severe droughts when other lakes drop dramatically.

The shoreline is characterized by coarse sandy soil and large pink gneiss formations — metamorphic rock approximately 1.1 billion years old, part of the Precambrian core of the Llano Uplift. The rock is smooth and rounded from water erosion, creating natural platforms for sunbathing and launching points for swimmers.

The most prominent feature is Devil's Waterhole, located on an eastern branch of the lake where Spring Creek merges with the main body of water. The pool is approximately 20 feet deep at its center, surrounded on three sides by steep granite cliff faces ranging from 10 to 25 feet in height. The cliffs are used for jumping — the lower ledges at 10 to 12 feet are accessible to most visitors, while the higher points at 20 to 25 feet draw more experienced jumpers. The water below is deep enough to be safe at all normal lake levels, though the park service posts warnings and the area is unsupervised. On summer weekends, Devil's Waterhole draws hundreds of visitors and the trail to reach it fills early.

Longhorn Cavern

Longhorn Cavern is a river-formed limestone cave located on Backbone Ridge, approximately halfway along Park Road 4. Unlike most Texas caves, which were formed by the dissolution of limestone by groundwater seeping downward, Longhorn Cavern was carved by an underground river flowing horizontally through the rock. This process created unusually large, open passages — some rooms are 100 feet wide and 30 feet high — with smooth, water-polished walls rather than the typical stalactite formations found in drip-formed caves.

The cave maintains a constant temperature of 68 degrees Fahrenheit year-round. Guided walking tours cover a 1.1-mile round trip through the developed sections, taking approximately 90 minutes. Notable features along the tour include:

* The Indian Council Room: A large, open chamber with a natural chimney that draws air upward, creating a natural ventilation system. Archaeological evidence suggests the room was used by Native Americans for shelter and gatherings.

* The Crystal City: A section of the cave where calcite crystal formations cover the walls and ceiling, creating a reflective, glittering surface when illuminated.

* The Queen's Throne: A large flowstone formation shaped by thousands of years of mineral-laden water flowing over a central rock.

* Sam Bass's Outlaw Hideout: A chamber near the cave entrance where, according to local tradition, the outlaw Sam Bass and his gang hid stolen loot in the 1870s after robbing stagecoaches in the area.

The cave has served many purposes over the centuries: Native American shelter, Confederate gunpowder storage during the Civil War, a dance hall and speakeasy during Prohibition (a wooden dance floor was installed in one of the larger chambers), and finally a state park.

The Geology of the Drive

Park Road 4 crosses one of the most visible geological transitions in Central Texas. At the northern end, near Inks Lake, the road passes through the Precambrian granite and gneiss of the Llano Uplift — rock that is over one billion years old and represents the exposed core of an ancient mountain range. The pink and gray boulders along the lakeshore are Valley Spring Gneiss, a metamorphic rock that predates most life on Earth.

As the road climbs south toward Backbone Ridge, the geology shifts to Cretaceous limestone — rock deposited approximately 100 million years ago when a shallow sea covered Central Texas. The transition is visible in the road cuts: pink granite gives way to gray and tan limestone over a distance of just a few miles. Longhorn Cavern itself is carved entirely within this limestone layer.

This geological transition — from the ancient Precambrian core to the younger limestone cap — is the defining feature of the Llano Uplift and is rarely as visible or accessible as it is along Park Road 4.

Wineries Along the Corridor

Hoover's Valley, located along the western section of Park Road 4, has developed into a small wine-growing area. The limestone soils, southern exposure, and elevation (approximately 1,000 feet) create conditions suitable for several grape varieties.

Food and Drink

Dining options directly on Park Road 4 are limited. For full meals, visitors typically drive to Burnet (10 minutes east) or Marble Falls (20 minutes southeast).

Where to Stay

Inks Lake State Park offers nearly 200 campsites, ranging from primitive walk-in sites to those with water and electric hookups, as well as limited cabin rentals. The park's campsites are among the most popular in the Texas state park system and frequently sell out months in advance for spring and summer weekends. There are no hotels directly on Park Road 4; visitors seeking traditional lodging typically stay in nearby Burnet or Marble Falls.

Practical Information

* Getting There: Park Road 4 connects U.S. Highway 281 (south of Burnet) to State Highway 29 (west of Burnet). The drive takes about 25 minutes without stops.

* Time Needed: Plan for a half-day minimum. A full day allows for swimming at Devil's Waterhole, a cave tour at Longhorn Cavern, and a wine tasting.

* Fees: Inks Lake State Park charges a $7 daily entrance fee for adults. Longhorn Cavern cave tours are separately ticketed (approximately $20 for adults, $12 for children).

* Reservations: Campsites at Inks Lake and cave tour slots at Longhorn Cavern should be reserved well in advance during spring break and summer weekends.

* Swimming Safety: Devil's Waterhole is unsupervised. Cliff jumping carries inherent risk. The park posts depth markers and warning signs but does not station lifeguards.

Why It Matters for the Hill Country

The Park Road 4 corridor preserves a specific era of Texas history, showcasing both the geological forces that shaped the Llano Uplift over a billion years and the manual labor of the Civilian Conservation Corps that made these landscapes accessible in the 1930s. It provides a concentrated stretch of public land where the transition from Precambrian granite to Cretaceous limestone is visible from the road, where a constant-level lake offers reliable recreation regardless of drought, and where an underground river carved a cavern that has served as shelter, hideout, dance hall, and state park. It is the most geologically dense corridor in the Highland Lakes.