The 44-year-old Salisbury man was said to have answered the call of nature at the Stonehenge summer solstice celebrations. Wiltshire Police said the man had not been urinating on the historic stones, but had carried out the act "while children were present".
The annual celebration this year drew crowds of around 10,000 to watch the sunrise.
Three others were arrested at Stonehenge: a Warminster man, 25, on suspicion of drink driving; a 15-year-old girl from Bulford on suspicion of being drunk and disorderly; and a man, 19, from the Isle of Wight, on suspicion of criminal damage.
A 45-year-old man from Great Somerford was arrested on suspicion of common assault in Avebury.
Supt Dave Minty said: "We were pleased with how summer solstice went once again this year. It passed peacefully with just one arrest at Avebury and four at Stonehenge, including one person on suspicion of drink driving.
"Overnight, we deployed a force drone at Stonehenge several times to help keep an eye on the estimated 10,000 strong crowd.”