This diatopic study examines the characteristics of the locative adverb constructions that select possessive pronouns as complements in Peninsular Spanish oral corpora. Firstly, the range of locative adverbs that take part in this construction are scrutinised, as well as their frequency of use with respect to that of their counterparts, in which a prepositional phrase appears as a complement to the locative adverb. Secondly, the geographic spread within Spain and the diatopic differences between the various autonomous communities are discussed. Thirdly, this paper also explores the variation in use between the possessive affixes ‑ o and ‑ a and the motivations traditionally given for this variation: to wit, the analogy with the final vowel of the locative adverb and the agreement with the referent of the possessive pronoun. Finally, it is proposed that diatopy, not previously considered in the literature, might be an influencing factor in said variation, given that there appears to be a strong link between the region and the use of one or another desinence of the possessive. This is, for instance, the case for Andalusia, where the vast majority of the locative adverb cases with possessives exhibit the suffix ‑ a .