Actual work at the 2012 site of the US grand prix in Austin, Texas, got underway this week.
The organisers gained conditional planning permission two weeks ago, having announced earlier in 2010 that construction would begin in December.
Groundbreaking at the 970-acre site commenced this week near the future Turn 11, the local Austin American Statesman newspaper reports.
At work on Thursday was a small fleet of heavy machinery, and among the first tasks was silt fences, the drilling of holes for earth samples, and the staking out of the layout by vegetation shredders.
Organisers have said F1 authorities are advising them to have the circuit ready by June 2012, raising expectations the race will be paired on the calendar with Canada.