Hearst Castle is the No. 1 tourist attraction in the Tri-Counties.

San Luis Obispo, Santa Barbara and Ventura counties are hot spots for tourism with an array of attractions and activities enjoyed by visitors and locals alike. Here’s a look at the top three attractions in each of the Tri-Counties, ranked by number of annual visitors, according to the Pacific Coast Business Times 2018 Book of Lists:

SAN LUIS OBISPO COUNTY

1. Hearst Castle

The legendary estate of media tycoon William Randolph Hearst, Hearst Castle was originally called “La Cuesta Encantada” or The Enchanted Hill. Hearst began building on his ranch near San Simeon in 1919 — never finishing the entirety of his estate plans but leaving behind 165 rooms and 123 acres of walkways, pools, gardens and terraces as well as an extensive art collection. As an international attraction and the biggest in the Tri-Counties, Hearst Castle gets 800,000 visitors per year.

2. San Luis Obispo Museum of Art

The San Luis Obispo Museum of Art was started as an association in the 1950s by a group of local artists, educators and enthusiasts. Today, the museum hosts a collection of contemporary art focused on artists who live in California and on the Central Coast. It offers gallery tours and events, drawing 55,000 visitors per year to its location in downtown San Luis Obispo.

3. San Luis Obispo Children’s Museum

Featuring three floors of family-friendly fun and an outdoor playscape, the San Luis Obispo Children’s Museum is designed for children ages 1-10 and gets 50,000 visitors each year.

In 1990, the museum was established in what used to be an old transmission shop; renovations that added its second and third floors were completed in 2009.

SANTA BARBARA COUNTY

1. Santa Barbara Zoo

Home to 146 species of mammals, reptiles, birds and insects, the Santa Barbara Zoo rests on 30 acres in downtown Santa Barbara. Since opening in August 1963, it’s become the second biggest attraction in the Tri-Counties, visited by 450,000 people a year. Besides its 500 animals, the zoo features giraffe feeding, stage shows, guided tours and fitness classes. It also runs conservation and education programs.

2. La Purisima Mission State Historic Park

Dating back to 1787 when it was founded by Franciscans, La Purisima Mission State Historic Park was a ranchland where Chumash converts and Spanish settlers lived. The mission and other buildings were mainly destroyed and have been recreated in an authentic 1820s style. With 10 original buildings resting on 1,928 acres, the mission in Lompoc receives 200,000 annual visitors a year who come to experience its tours, trails and period exhibits.

3. Santa Barbara Museum of Natural History

A hands-on attraction that includes interactive exhibits, the Sea Center on Stearns Wharf and a planetarium, the Santa Barbara Museum of Natural History sits on 17 acres in Santa Barbara. It was founded in 1916 and has grown its collection to 3.5 million specimens of natural history. The nonprofit draws 200,000 visitors a year.

VENTURA COUNTY

1. Ronald Reagan Presidential Library and Museum

A notable historical landmark in the Tri-Counties and the third biggest attraction is the Ronald Reagan Presidential Library and Museum in Simi Valley.

The 100-acre campus houses several exhibits, including the Air Force One aircraft that flew seven U.S. presidents, a full-size replica of the White House Oval Office and the grave of the 40th president and his wife Nancy Reagan.

The library holds presidential records from the Reagan administration, with documents, film and audio tapes, photographs and more than 400,000 artifacts. It draws 400,000 visitors a year.

2. Ventura Botanical Gardens

Although currently closed for repairs due to most of its 109 acres burning in the Thomas fire, Ventura Botanical Gardens has operated in Ventura as a free attraction since around 2012. Since the fire, more than 1,000 plants have already been planted with others slowly growing back. The gardens were created as a cultural public space for the community, bringing in 90,000 annual visitors.

3. Museum of Ventura County

Celebrating the history, art and culture of Ventura County and the Channel Islands, the Museum of Ventura County is home to the Agriculture Museum in Santa Paula and the Ventura County Museum and Research Library in Ventura.

It was founded in 1913 with artifacts from a doctor who moved to Ventura after the Civil War. More than 30,000 works of art from various U.S. time periods are featured, as well as Chumash, Spanish and Mexican-American artifacts. The museum draws 60,000 visitors per year.

• Contact Annabelle Blair at ablair@pacbiztimes.com.