All four, two aged 13 and two aged 14, have been bailed pending further inquiries following the attack in Workington, Cumbria, on Tuesday.
The victim was walking along Black Path when she was raped close to Cloffocks car park at about 19:00 GMT.
A fifth boy, aged 13, was arrested on suspicion of rape and later released without charge.

Walkers have been warned to keep away from the site at Seaford Head, with the coastguard warning it could fall away at any time.
Amanda Death, who lives in Seaford, spotted the crack and alerted Newhaven Coastguard after going out for a walk with her daughter.
Coastguard spokesman Graham Easton said there had been cliff falls at Seaford, Birling Gap and Hastings this year.
"It could go at any time but it could hang on for quite a long time," he said.
"The advice is simple to stay away from cliff edges - but equally we want people to stay away from the base of cliffs.
"They can be crumbly and fall away and obviously a big crack like this would cause a massive cliff fall but even small rocks will cause a lot of damage if you're underneath at that sort of height."
BBC reporter Lucinda Adam estimated the crack was about 6ft (1.8m) to 7ft (2.1m) long.
She said the land above the crack was on the other side of the safety fence, closest to the sea.
Mrs Death said she went to have breakfast on the beach with her daughter on Saturday and spotted the crack when the pair walked further along the coast.
She said she stayed back from the edge but was able to zoom in on the crack with her phone and added: "It looks like it could go pretty soon."
Seaford is the start of a six-mile (10km) stretch of protected limestone sea cliffs that lead up to Beachy Head, according to Natural England.
Walkers follow a cliff top footpath from Seaford to reach Hope Gap and Cuckmere Haven.

An extra 260,000 passengers used the airport compared with the same month in 2014, mainly due to an increase in long-haul flights and larger aircraft.
In June, Gatwick said it had the busiest year in its history, claiming it proved its case for a second runway.
The Airports Commission has since backed a new Heathrow runway instead.
Gatwick said demand for long-haul flights to New York, Los Angeles, Cape Verde, Trinidad and Costa Rica had contributed to the increased passenger numbers.
It said it had now experienced two-and-a-half years of consecutive month-on-month growth.
Gatwick's chief executive Stewart Wingate said the July figures showed his airport remained the best location for the new runway.
"These results put us 10 years ahead of the forecasts used by the Airports Commission to predict future air traffic movements," he said.
"Our growth in the last 12 months is actually more than the commission concluded could be added at Gatwick in the first year of a new runway.
"This is further proof of the flaws in the Airports Commission analysis and shows its conclusions are fast unravelling."
A spokesman for the commission said: "All forecasts in the Airports Commission final report were subject to extensive analysis and we are confident that they are fit for purpose."

The rare plants around Dinas Bran, a medieval castle and iron age hillfort above Llangollen and the Dee Valley, have been awarded national recognition.
Natural Resources Wales says important species of birds and butterflies "rely on the grassland and other habitats".
It is also home to upright chickweed, shepherd's cress and greater broomrap.
"The grasslands found here are scarce in lowland Britain," said Richard May, conservation officer for NRW.
"And Dinas Bran has the second largest area in Wales of one type of acid grassland."
The remains of Dinas Bran castle and hillfort date back to the occupation of the princes of Powys Fadog in the mid 13th century and they have been protected since 1957.
"Dinas Bran is hugely popular with walkers, attracting thousands of people a year to visit the iron age hillfort and medieval castle set in a spectacular landscape," added Mr May.
"By working in partnership with landowners, we look forward to helping to manage the site's special features so that we and future generations can continue to enjoy Dinas Bran's rich natural and historical heritage."
Four teenage boys arrested after a 15-year-old girl was raped have been released on bail.
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A large crack has appeared in a cliff face in East Sussex.
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Gatwick had its busiest July with 4.3 million passengers - a 6.4% increase on last year - the West Sussex airport has said.
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A "scarce" grassland around the ancient ruins of a Denbighshire castle has been protected as a site of special scientific interest.