Jones County, Mississippi, is supplied with groundwater from aquifers in strata of Eocene and younger age. The largest groundwater withdrawals are from aquifers in the Catahoula Sandstone of the Miocene aquifer system that occur at depths of 200 and 400 ft in the Laurel area. Several public and industrial water supply wells obtain water from deeper Eocene strata that occur at depths of more than 900 ft. Pumpage from all aquifers in Jones County for all uses increased from < 1 million gal/day (mgd) in 1925 to a maximum of 21.6 mgd in 1975. The city of Laurel used about 6.2 mgd in 1984 and total water use for the county was about 14.1 mgd. The extreme irregularity of the sand beds that form the aquifers is reflected in the wide range in hydraulic characteristics. Transmissivity values range from 600 to 10,000 sq ft/day and average about 6,000 sq ft/day. The average hydraulic conductivity is about 90 ft/day. Water levels in key observation wells in the lower Catahoula aquifer at Laurel have declined from about 150 ft above sea level in 1945 to about 80 ft above sea level in 1985. Since 1975, water levels in the Catahoula aquifers in the Laurel area have declined at a slower rate, but the cone of depression has enlarged because of areal changes in pumping. Water in the major aquifers is usable for most purposes, and concentrations of common constituents do not exceed water quality criteria for drinking water supplies. Iron concentrations are highest in the Catahoula and Vicksburg aquifers, exceeding 0.30 mg/L in water from 33% of the wells for which data are available. Color is highest in the Eocene Cockfield aquifer, exceeding 50 units in water from 60% of the wells. Dissolved solids concentrations range from 487 to 840 mg/L in water from wells in the Cockfield and Sparta aquifers. The pH values generally are < 7.0 in water from wells in the Catahoula and Vicksburg aquifers and > 8.4 in water from wells in the Cockfield and Sparta aquifers. Hardness of water from all aquifers rarely exceeds 50 mg/L. (Lantz-PTT)