On 18th December 1779, Luis Meagher y O'Brien, native of County Limerick, Ireland, married at the Naval chapel of Ferrol's Esteiro shipyard. The groom, referred to as Don Luís, was stated to be the son of Don Dionysus Meagher and Doña María O'Brien, deceased residents of Ferrol; the bride, Doña Margarita 'Laugna', was stated to be subject to military jurisdiction (hence the parish at which the marriage took place) and a daughter of Don Juan 'Laugna' and Catalina Smith. The witness was one Guillermo Cail.
Mónica Amenedo Costa, of Spain's University of La Coruña, has published a valuable study of the spelling corruptions of foreign surnames that occur in contemporary records, and suggests that 'Juan Laugna' actually refers to one John Loughnan. As for Lewis Meagher, he's been mentioned in other studies, such as that of Alfredo Martín García, which suggest that Meagher didn't fit the traditional image of Irish 'wild geese', inasmuch as he seems to have accepted the post of British vice-consul in the area; and he was also subsequently American consul to Santander. As far as I can tell no publication mentioning Meagher has yet disclosed his parentage, which is given above in the hope that someone can attach him to their tree as appropriate.
SOURCES: Iglesia Castrense de San Fernando de Esteiro, Matrimonios 1778-1792, Folio 58, Archivo del Museo Naval, Madrid, AMN 1468-02B; Revista Electrónica de Lingüística Aplicada (ISSN 1885-9089). 2009, Número 8, páginas 211- «CUADERNOS DE ESTUDIOS GALLEGOS», Tomo XLVIII, Fascículo 114, Pp. 131-160, Santiago 2001.