The speaker is talking about someone he loves, and he describes her in terms of a place. Her "home" is a "mad country," and he promises to give himself to it. The word "mad" suggests somewhere wild, unpredictable, maybe even unreasonable, yet he chooses it anyway. That choice feels like a vow, a kind of emigration of the heart. The title, "Migrant," fits: loving her means leaving his own ground and settling in hers.
In the second stanza, the focus shifts to her face. The lines on it are compared to a picture "drawn by time," almost like a map. Her years, her experiences, and perhaps her troubles are all written there, and the speaker reads them closely. The mood is tender and quietly devoted. There is a hint of risk in that "mad" country, but the poem's tone is calm and accepting. He doesn't want her smoothed out or changed; he wants to belong to her as she is.