“Everywhere in North America Rotary Clubs came into existence by the hundreds and the thousands. Professional organizers were unnecessary. Every club had the impulse to pass on to other cities the idea which it had found so beneficial in its city. Clubs were grouped into districts and local Rotarians were elected annually as "district governors." They accepted the responsibility for extension in their districts and for the further advancement of Rotary's objects and practices. They and their colleagues, the governors of districts in all parts of the world, have been and always will be the great unifying and steadying force of Rotary.” Paul P. Harris, This Rotarian Age, 1935 Chapter 34

1915 War service of clubs in Great Britain and Ireland intensified: Entertainments for wounded soldiers; combat battalions raised; Rotary companies of special constabulary organized. New standard club constitution and model by-laws adopted at the San Francisco convention for all new as well as existing clubs, includes a provision for “additional active members, previously known as partnership, associate, or second active member. The “Rotary Code of Ethics” was adopted and during subsequent years come into wide usage until general distribution was discontinued (1927-28). Rotary system of districts enlarged and term “Governor” established. Charter No. 200 issued to new club organized at Columbus, Ga., U.S.A. -- Appendix to My Road to Rotary 1948 Rotary International (1915)

In the early days, the post was not called Governor and the grouping e.g. the B.A.R.C was not called a district.  In 1915 the San Francisco Convention adopted a constitution for the I.A.R.C. which divided the existing clubs into 10 geographical districts, each to have a 'District Governor'. RGHF senior historian Basil Lewis, England 16 July 2009

Governors: The 1915 Convention approved a report from Arch Klumph and a committee to create 10 geographic 'districts' with all the clubs then in existence.  The convention then agreed that the leader of each district should be called The District Governor. (Source: "A Century of Service", page 61, Rotary International, David Forward.

From the beginning of the first Rotary Club in Chicago, until 1915, there were no Rotary Districts. Clubs acted independently and came together in exchanges between clubs that were geographically close in proximity, and at national meetings organized by Paul Harris and Ches Perry of the Chicago club.

H. J. “Bru” Brunnier was President of the Rotary Club of San Francisco in 1914. He is recognized as the originator of the district idea in Rotary. His idea came about during a regional fellowship gathering at a six-city meeting in Tacoma, Washington. Returning by train from Seattle following the conference, Bru awakened in the middle of the night with his idea. He summoned a porter to bring him a railroad schedule of the United States, which also included a map of the USA. Bru’s involvement in Rotary provided him with knowledge of the location of most of the 100 clubs in Rotary at that time. He placed them on the railroad schedule map with dots to show their location. He then combined the clubs on the basis of rail transportation and arrived at 13 groupings. His map and his idea formed the basis upon which Rotary leaders adopted the district plan at the Rotary Convention of 1915 in San Francisco. -- From the history of District 5150 by PDG and RGHF member Bill Sturgeon, USA