More people than ever before were counted visiting the Saint Croix National Scenic Riverway in 2014. The National Park Service released the data recently, adding the disclaimer that the numbers may have increased in part due to more accurate counting methods.

Approximately 671,582 people visited the federally-managed St. Croix and Namekagon Rivers last year, almost double the 2013 numbers.

Estimating visitor numbers is difficult because of the many free access points to the river. Unlike many other National Parks, no entrance fees are collected on the St. Croix, so firm data is hard to come by.

“If we collected a fee I would have a much better idea,” riverway spokesperson Julie Galonska told the Star Tribune.

In addition to doing random counts of river users, the Park Service also relies on outfitters and other businesses to report their customer numbers. Canoe and kayak outfitters Wild River Outfitters in Grantsburg also reported an increase in its business last year, after mostly steady numbers for the previous decade.

The Park Service looks for trends in the data that will help it manage the riverway’s facilities and natural resources. According to Galonska, they can study the information to see where use is concentrated, possible impacts on water quality, wildlife, and other effects.

Read more at the Star Tribune or see the data for yourself (search for “Saint Croix NSR”).