By CASSANDRA MICKENS / Associate Editor

NORTH SHELBY — Oak Mountain High School is among the more than 2,000 public and private high schools listed on The Washington Post’s Most Challenging High Schools index, which ranks the toughest schools in the nation.

Oak Mountain is ranked No. 4 statewide and No. 565 nationally. The Washington Post ranks schools via a simple ratio — the number of college-level tests given at a school in the previous calendar year divided by the number of graduates that year.  A ratio of 1.000 means the school had as many tests as graduates.

With an index ratio of 2.864, Oak Mountain has a 99 percent four-year graduation rate and an average ACT score of 24.4. In addition, Oak Mountain has an average SAT score of 1,672, and 80 percent of its students attend four-year colleges.

Oak Mountain was previously ranked as the fifth most challenging school in the state in 2011 and 2012.

“I am so proud of our students and staff for achieving this great distinction,” Principal Joan Doyle said in a Shelby County Schools news release. “Everyone is always going the extra mile to make sure that our students have the very best academic opportunities.”

Jefferson County International Baccalaureate School in Irondale ranked as the No. 1 most challenging in the state. Jefferson County IB ranked No. 12 nationally. Other Birmingham-area schools listed include No. 3 Mountain Brook High School (No. 469 nationally) and No. 5 Homewood High School (No. 843 nationally).

For the complete list, visit washingtonpost.com/highschoolchallenge.