A two-month investigation by San Mateo County Narcotic Task Force netted nearly $23 million worth of illegal marijuana plants in the county, officials said.

Two Redwood City residents, 38-year-old Joaquin Sanchez and 32-year-old Joel Ochoa Sanchex, were arrested after authorities said they were found near the grow site — a public open space area in the county.

The pair, along with Mexico residents Juan Farias Galeana and Jose Antonio Mendoza, are accused of illegally growing 11,400 marijuana plants and environmental violations, said Saul Lopez, commander of the San Mateo County Narcotics Task Force.

Lopez said the group worked with several other agencies to scout historical sites and collect anonymous tips in order to locate the fields, which were hidden at the Midpeninsula Regional Open Space District.

"In several grow sites various supplies were located within the grow sites indicating that the suspects stayed at the gardens for long periods of time," the agency wrote in a statement.

Officials say the illegal activity caused deforestation, damage to wildlife habitats and posed a danger to citizens from its hazardous-chemical pollution.

Anyone with information regarding any of the illegal grows can call the San Mateo County Narcotics Task Force anonymously at 650-573-3991.