They had been lying in the road with their arms locked into metal tubing.
A North Yorkshire Police spokesman today said: "Four women - aged 39, 40, 54 and 66 - have been charged with wilfully obstructing the highway.
"They will appear at York Magistrates' Court in November."
A total of 24 people have been arrested at the site so far this month.
Two were released with no further action, two accepted cautions, and the remaining 20 have been charged with offences including obstructing the highway, assaulting a police officer and obstructing a police officer.
Yesterday's protest was the latest in a string of demonstrations to have taken place in recent weeks, ahead of planned fracking at the site off Habton Road later this year.