Aliso Viejo (Spanish for "Old Sycamore") is a city in the San Joaquin Hills of southern Orange County, California.

The Acjachemen are the Indigenous people of Aliso Viejo, who lived in the area for thousands of years.

With the arrival of settlers, the Acjachemen village sites would later become the southern areas of the Moulton Ranch.

[5] The planned community of Aliso Viejo's original 6,600 acres (2,700 ha) were once part of the 26,000-acre (11,000 ha) Moulton Ranch, owned by the Moulton family, who took title in the 1890s to land originally granted to Juan Avila by the Mexican government in 1842.

The master plan was approved by the Orange County in 1979, and homes were first offered for sale in March 1982.

As part of the project, 2,600 acres (1,100 ha) were dedicated to Orange County as part of the Aliso and Wood Canyons Wilderness Park, and 800 acres (320 ha) were set aside for local parks, recreation, schools and community facilities.

It was the first community-wide association of its kind in California and has the unique ability to provide a full range of community services and facilities.

Every home in Aliso Viejo was located within 1+1⁄2 miles (2.4 km) of Pacific Park, to encourage live-and-work opportunities.

The City Council of Aliso Viejo consists of five members serving staggered four-year terms.

Much of the city rests on the east slope of the San Joaquin Hills, which are a coastal mountain range extending for about 15 miles (24 km) along the Pacific coast.

Aliso Viejo city officials famously came close to banning polystyrene cups in 2004 after a paralegal working for the city discovered the dhmo.org parody website and learned that they contain "dihydrogen monoxide", failing to realize that this is simply an alternative name for water.

[47] In October 2005, the city gained national media attention once again when 19-year-old resident William Freund donned a cape and mask, and murdered two of his neighbors, 22-year-old Christina Smith and her father Vernon, before killing himself.

[48][49] Freund had Asperger syndrome and posted on an Internet message board for people with the disorder, in which he talked of suicide and acts of violence.

[50] On November 17, 2006, the family of the two victims sued Freund's parents for "wrongful death and emotional distress.

"[51] Freund lived with his parents at the time of the shooting and had a history of mental disorders including Asperger syndrome and attention deficit disorder, but the court ruled that Freund's parents were not liable for his actions because he was an adult at the time and the attacks were unforeseen.

[53] A story on the school was featured on the national television program, Geraldo at Large and the BBC also covered the dance ban.

[54] In 2008–early 2009, Aliso Viejo residents were protesting the United States Postal Service's plan to build a large mail distribution facility.

The proposed facility would have up to 500 employees and USPS trucks traveling over residential streets 24 hours per day.

On March 9, 2009, the USPS announced that it would not move forward with plans to build the distribution facility due to the economic outlook at the time.