The District of Columbia Grotto can rightfully claim to be the birthplace of today's organized caving in the United States. Due in considerable measure to the vision of the late William J. Stephenson of the U.S. Patent Office, what began as a small local group in 1939 has grown to be the National Speleological Society, with nearly two hundred local grottos (chapters) across the country and over ten thousand individual members.

It all started when a feature story in the Washington Star in 1939 about Mammoth Cave and Carlsbad Caverns caught the eye of Stephenson and his wife Merle of Washington, D.C. For some years they had been exploring caves in northern Virginia with various colleagues and other friends. This activity had begun when Stephenson, who was the leader of a hiking group connected with his church, decided one day to take a trip to a cave. After that, cave exploring became the principal focus of the group. What caught Stephenson's eye in the Star article was the sentence: "In England there is a national organization devoted to caving." Stephenson immediately recognized the many advantages such an organization could have for the United States and he set himself the task of establishing one.

On May 6, 1939, the Speleological Society of the District of Columbia became a reality. Within a year, a significant proportion of the members were found to come from outside the Washington area. As a result, the officers of the D.C. group drafted a constitution for a proposed National Speleological Society in the fall of 1940. By January of 1941 the new national organization had been established. The Society soon had two chapters, the New England Grotto and the District of Columbia Grotto.

Establishing the age of the D.C. Grotto, however, would be difficult. In the fall of 1942, with the United States at war, the caving group in the nation's capital became temporarily inactive. The more active individuals were employed by the U.S. Patent Office, which was transferred to Richmond, Virginia, where they continued their interest in cave exploration during the war years. The chapter in Washington was not revived until 1946, when it took the name "Grotto," as is customary for most NSS chapters. Even more confusing for a historian is the cover of the October 1949 grotto newsletter, identified as Vol. III, No. 10, but featuring a birthday cake and the caption, "Our First Anniversary." With so much uncertainty surrounding a determination of age, the D.C. Grotto must be a female! Is her age to be dated from the foundation of the Speleological Society of the District of Columbia in 1939, assuming that the uninterrupted activities of her founding members in Richmond entitle one to count the war years? Or does the age start from the formal revival of the chapter in 1946 (which agrees with the volume numbering of the October 1949 newsletter)? Or is she even younger, judging by the birthday cake caption?

The District of Columbia Grotto was incorporated in the District of Columbia in 1979. In 1992 it was reincorporated in the State of Maryland. It has also qualified with the Internal Revenue Service as eligible to receive tax-deductible contributions as a scientific organization under Section 501(C)(3) of the Internal Revenue Code.