She was summoned for questioning after a video of her dressed in "indecent" clothing sparked a heated debate in the Muslim country.
Some demanded she be punished for breaking the strict Saudi dress code.
But the public prosecutor has now closed the case, the ministry of information said.
She was released on Tuesday after being questioned, having admitted walking through the site with her hair uncovered and wearing a skirt.
Women in Saudi Arabia must wear loose-fitting, full-length robes known as abayas in public, as well as a headscarf if they are Muslim.
However, there are no restrictions on what women can wear under their abayas.
According to the ministry, she did not know the video had been uploaded.
It was first shared on Snapchat over the weekend by a user called "Model Khulood".
It shows a woman walking along an empty street in a fort at Ushayqir Heritage Village, about 155km (96 miles) north of the capital Riyadh, in Najd province.
End of Twitter post  by @50BM_
Najd is one of the most conservative regions in Saudi Arabia. It was where the founder of Wahhabism - the austere form of Sunni Islam that is practised by the Saudi royal family and religious establishment - was born in the late 18th Century.
The video was quickly picked up by Saudis on Twitter, where critics used the hashtag "demand_the_trial_of_Model_Khulood".
Others came to the woman's defence, praising her "bravery" and insisting that she ought to be allowed to wear what she wanted.
Women are also banned from driving, are separated from unrelated men, and must be accompanied by or receive written permission from a male guardian - usually a father, husband or brother - if they want to travel, work or access healthcare.
Saudi police have released a young woman who appeared in a video wearing a miniskirt and crop-top in public without charge.