The 160-acre Marshall Landfill site is located in Boulder County, Colorado. The site consists of two adjacent landfills, each about 80 acres in size. The Marshall Landfill, in the northern portion of the site, operated between 1965 and 1974. The Boulder Landfill to the immediate south operated between 1974 and 1992. Landfill operations contaminated soil, groundwater, surface water and sediment with hazardous chemicals. Remedy construction finished in 1993. Operation and maintenance activities and groundwater monitoring are ongoing.