Almost 1,500 children in Kirklees travel to Calderdale to go to school, figures have revealed.
Data released by the Department of Education show that 1,481 school places in Calderdale are taken up by children whose homes are within Kirklees.
The data also revealed that 266 children in Calderdale take up places in Kirklees schools.
Schools in Calderdale were recently revealed to deliver the best GCSE results in West Yorkshire, with 61.8% of pupils achieving five or more grades A*-C in English and Maths.
The same was true for only 56.8% of Kirklees pupils.
Altogether, 2,990 children in Kirklees took up places in outside schools last year, including 945 in Leeds, 403 in Wakefield and 161 venturing to Bradford.
In comparison, 1,183 children in West Yorkshire travel to school in Kirklees.