Into the 1870s, the town was little more than a frontier trading center, with a few log buildings housing business establishments, a post office, and a few homes.

In 1879, the first bank, Moore, Foster, and Company, was founded, and during the 1880s, Llano acquired a number of new enterprises that served the county's farmers and ranchers.

After the county outgrew the one-story stone building that had housed its public offices, in 1885, an ornate brick courthouse was completed on the square on the south side of the river.

In the 1880s the Llano Rural, the town's first newspaper, was established, followed by the Iron City News, the name of which reflects growing interest in the county's mineral resources.

In 1892, at the peak of the boom period, the town was incorporated, the river was bridged, and the Austin and Northwestern Railroad was extended to a terminal on the north side of Llano.

Many of the new businesses were begun in the boom period, and substantial brick establishments were constructed around the public square on the north side of the river.

Because the county's mineral resources, with the significant exception of granite, did not exist in commercially exploitable concentrations, the boom period soon faded.

Plans to connect Llano with Fredericksburg via an extension of the San Antonio and Aransas Pass Railway were not fulfilled.

In the 1920s, Llano was a major shipping point for cattle; the cotton industry flourished in the county through the 1930s, but declined thereafter into insignificance.

By 1964, the town had a new hospital, a post office, school buildings, a community center, a rodeo area, and a golf course, along with a city park and improved water system.

Llano was an important link in the Highland Lakes chain of tourist areas, and attracted many hunters during the deer season.

[8] In 2021 County Judge Ron Cunningham removed books, such as In the Night Kitchen, from the shelves of the main library because they contained nudity.

The bald eagle makes its home in Llano County during its annual winter migration with most birds found around the Lake Buchanan area.

Llanite, a rare type of brown rhyolite porphyry with sky-blue quartz crystals and rusty-pink microcline feldspar, is found nowhere else in the world except in Llano County.

The centuries-long habitation of various Native American tribes in the area has produced numerous archaeological sites which attract amateur archaeologists year-round.