Ever since its founding in 1925 the “headquarters” of the IARU has been provided by the ARRL, the national association for amateur radio in the United States. Under the current IARU Constitution this function is called the International Secretariat. The ARRL is the largest of the IARU member-societies and has the largest full-time staff, and so is in the best position to provide continuity and funding.
The mailing address of the International Secretariat is P.O. Box 310905, Newington, CT 06131–0905 USA. The physical address is that of ARRL Headquarters: 225 Main Street, Newington, CT 06111 USA. Email: email@example.com.
The IARU Constitution and Bylaws set out the procedure for the selection of another member-society to serve as the International Secretariat should that become necessary or desirable.