Despite the common language, barriers to entry into the US market are high. For example, every design office must employ locally qualified staff to sign off drawings done by colleagues from other states or countries.
As a result, most British firms have decided that buying a local firm is the quickest way to establish a presence to build on.
Mott MacDonald has the longest standing stake, having set up a joint venture with mining company Hatch in the 1960s. The venture worked on major projects including the Boston Harbour clean up and the Los Angeles metro. Now it is working for California's valley transit authority on a series of road and light rail projects near San Jose.
Mott MacDonald has stepped up its involvement in the US with the acquisition of US water engineer Killam. It hopes to grow this business on the back of a major water and sewage treatment spending programme.
WSP has also bought a US presence. Last year it acquired high rise structures consultant Cantor Seinuk, which has 150 staff, plus mechanical and electrical firm Flack & Kurtz.
WS Atkins has bought into the market with the purchase of Oklahoma City based multidisciplinary firm Benham as part of its strategy to establish trading hubs in major markets across the globe.
'We want to have between 3,000 and 5,000 staff in the US, ' says Atkins director Richard Cuthbert. Currently US staff number 1,000.
The exception to the rule is Arup. It initially set up on the west coast in the 1980s after winning work on hospitals through an Anglo American architect. Since then Arup's US operation has grown organically from bases on the east and west coasts to a point where its US operation now has around 500 mainly American staff covering civil and structural engineering as well as seismic, fire and acoustic disciplines.