[6] The United States' oldest cross country running event, the Dipsea Race, takes place annually in Marin County, attracting thousands of athletes.

Modern mountain biking has many early origins on the slopes of Mount Tamalpais in Marin.

Thousands of years ago, Coast Miwok people first populated the area today known as Marin County.

In 1967, the Marin Museum of the American Indian was established, with exhibits focusing on Coast Miwok artifacts, crafts, and artwork.

[10] As of 2021, Indigenous-led events include healing drumming, dogbane cordage demonstrations, trade feasts, and traditional dancing.

[11] During the Mexican-American war, areas of Marin County were seized by Americans as part of the conquest of California (1846–1847).

Marin / Marino was born into the Huimen people, a Coast Miwok tribe of Native Americans who inhabited the San Rafael area.

Starting in 1817, he served as an alcalde (in effect, an overseer) at the San Rafael Mission, where he lived from 1817 off and on until his death.

In 1821, Marino served as an expedition guide for the Spanish for a couple of years before escaping and hiding out for some months in the tiny Marin Islands (also named after him); his recapture resulted in a yearlong incarceration at the Presidio before his return to the Mission San Rafael area for about 15 years until his death in 1839.

[15] In 1595, Sebastian Cermeno lost his ship, the San Agustin, while exploring the Marin Coast.

However the first Spanish settlement in Marin was not established until 1817 when Mission San Rafael Arcángel was founded partly in response to the Russian-built Fort Ross to the north in what is now Sonoma County.

According to the records at the County Assessor-Recorder's Office, as of June 2006, Marin had 91,065 acres (369 km2) of taxable land, consisting of 79,086 parcels with a total tax basis of $39.8 billion.

There are also a considerable number of protected plant and animal species present: Fauna include the California red-legged frog (Rana draytonii) and California freshwater shrimp while flora include Marin Dwarf Flax, Hesperolinon congestum; Tiburon Jewelflower, Streptanthus niger; and Tiburon Indian paintbrush, Castilleja neglecta.

Notably, the Lagunitas Creek Watershed is home to the largest remaining wild run of coho salmon (Oncorhynchus kisutch) in Central California.

These coho are part of the "Central California Coast Evolutionarily Significant Unit,[17] " or CCC ESU, and are listed as "endangered" at both the state and federal level.

Strong efforts are also being made to protect and restore undammed, headwater reaches of this Watershed in the San Geronimo Valley, where upwards of 40% of the Lagunitas salmon spawn each year and where as much as 1/3 of the juvenile salmon (or fry) spend their entire freshwater lives.

The "Salmon Protection and Watershed Network"[19] leads winter tours for the public to learn about and view these spawning salmon, and also leads year-round opportunities for the public to get involved in stream restoration, monitoring spawning and smolt outmigration, juvenile fish rescue and relocation in the summer, and advocacy and policy development.

[23] When Richard Henry Dana Jr. visited San Francisco Bay in 1835, he wrote about vast tule elk (Cervus canadensis nannodes) herds near the Golden Gate on December 27: "...we came to anchor near the mouth of the bay, under a high and beautifully sloping hill, upon which herds of hundreds and hundreds of red deer [note: "red deer" is the European term for "elk"], and the stag, with his high branching antlers, were bounding about...," although it is not clear whether this was the Marin side or the San Francisco side.

Individuals born in Europe were the second largest foreign-born group; they made up 25.3% of Marin County's foreign population.

Lastly, residents born in Oceania made up a mere 1.2% of Marin County's foreign population.

[51] The Central Marin Police Authority is responsible for law enforcement in Larkspur, Corte Madera, and San Anselmo.

The first formal fire department in what is now Marin County was The Tamalpais Forestry Association, formed around the turn of the 19th century.

[52] The California State Legislature had been discussing legislation for forest-fire suppression as early as 1881, but the formal department did not come into being until approximately 1901.

The Marin County Fire Department came into existence in its current incarnation on July 1, 1941, with passage of an ordinance and two resolutions by the Board of Supervisors.

Marin has voted for many gubernatorial candidates who went on to become high-profile national figures, including Richard Nixon, Ronald Reagan, Jerry Brown, and Dianne Feinstein.

[citation needed] Due to the rapidly expanding nature of California's population, Marin's congressional district has changed numerous times over the decades.

[citation needed] In 2002, former U.S. President George H. W. Bush denounced convicted American Taliban associate John Walker Lindh as "some misguided Marin County hot-tubber," as a reference to the county's liberal, "hippie" political culture, mispronouncing "Marin" as he did so.

Outraged by the label, some local residents wrote scathing letters to the Marin Independent Journal, complaining of Bush's remarks.

In response, Bush wrote a letter to readers in the same newspaper, admitting regret and promising to not use the phrases Marin County and hot tub "in the same sentence again.

As of 2019[update] service operates from Sonoma County Airport to six stations in Marin ending near Larkspur Landing.