Ogden, formerly part of power and infrastructure company Ogden Corporation, has 650 professional staff and an annual revenue of £55m.
The acquisition enhances Amec's presence on America's east coast and brings the total staff number in its earth and environmental division to 2200, with an annual revenue of £138m.
The move comes after Amec's merger earlier this year with Canadian professional engineering and environmental services firm Agra.
Ogden's strengths include environmental risk assessment, hazardous waste remediation and water resource planning. It has government and private sector clients in the oil and gas, mining and transport sectors.
Amec chief executive Peter Mason said: "This addition provides greater geographical reach and complementary skills." Worldwide, Amec had a turnover of £3.1bn and made a profit of £77m in the 1999 financial year.
