Northampton, Lord and Lady, undated

As the correspondents in this sub-subseries make evident, McIlhenny cultivated a social network that reached across noted names in all the arts, as well as titled gentry, royalty and political figures. Whenever celebrities of the stage, screen or concert hall were performing in Philadelphia, McIlhenny would invite them to his home at Rittenhouse Square, just a stone's throw away from the major theatres and hotels. Although they could not always accept the offer, invitees included Noel Coward, Cole Porter, Vivien Leigh, Helen Hayes, Gian Carlo Menotti and Anna Moffo. When they did come, they apparently enjoyed themselves. In a 1950 letter to the British artist Derek Hill, McIlhenny writes that he threw a terrific party for Tallulah Bankhead one Saturday night, and that she did not leave until 6:15 the next morning. Numerous ladies, lords, marquises, and the like comprised McIlhenny's European correspondents. Most of those letters pertain to scheduling stateside visits with McIlhenny, during those months when he wasn't vacationing abroad. Sharing McIlhenny's enthusiasm for travel was another correspondent and personal friend, Gloria Etting, wife of Philadelphia artist Emlen Etting. In addition to her letters, clippings from Etting's newspaper column, "Philadelphians Abroad," are also included. In two of these articles, Etting writes exclusively of her 1956 and 1966 jaunts to Glenveagh. There is also a significant amount of correspondence with Lucy Porter, the previous owner of Glenveagh, who remained in contact with McIlhenny for nearly twenty years. Another correspondent with whom McIlhenny mixed business with pleasure is Angus Menzies. Menzies was a director of the General Trading Co., a London firm specializing in antiques, giftware, and interior decoration. As noted in one of Etting's 1952 columns, Menzies was also a traveling companion of theirs. In their twenty-year correspondence, McIlhenny relied on Menzies to furnish and decorate his homes in Philadelphia and Ireland as well as to select numerous wedding gifts, usually in the form of picnic baskets. Additional documentation of these transactions can be found in the "Art collection" series, filed under the firm name.

Although limited to a letter or two in each, several files underscore McIlhenny's reputation as a respected and sought-after authority of the fine and decorative arts. In a 1961 letter, Richard M. Nixon thanks McIlhenny not only for supporting his presidential campaign but also for agreeing to serve on the Committee of the Arts for Nixon-Lodge (the latter referring to Nixon's 1960 running mate, Henry Cabot Lodge). McIlhenny's support of Nixon apparently did not dissuade Jackie Kennedy from inviting him to join the advisory committee of the Commission of Fine Arts for the White House, which she initiated in 1962. The only evidence in these records of McIlhenny's involvement is an invitation to tea and a thank you from the First Lady. In a 1964 letter, Lady Bird Johnson invited McIlhenny to continue advising her and the Committee on the Preservation of the White House. Far richer in documentation is McIlhenny's participation as curator and advisor to the restoration of the Lancaster, Pennsylvania home of President James Buchanan. Because McIlhenny's extensive involvement with the project required him to be in contact with several individuals, he maintained the material under its organizational title, which cited correctly is the James Buchanan Foundation for the Preservation of Wheatland.

For some individuals, the only documentation consists of a note, usually of the person's address. In these cases, folder titles include "Note" after the person's name to indiciate that there is no correspondence. The "miscellaneous" alphabetical folders reflect original arrangement and identification. The final three folders, identified geographically, are thank you letters and other follow-up correspondence with various individuals with whom McIlhenny socialized while vacationing at those particular locales.