The idea of person is an analogical idea which is realised fully and absolutely only in its supreme analogue, God, the Pure Act. Let us recall further that, for St. Thomas, the intelligible value of “whole,” “totality,” is indissolubly bound to that of person…The concept of part is opposed to that of person.
Jacques Maritain, The Person and the Common Good, p. 40
God is unequivocally a Person (properly, Persons). Human persons are unequivocally persons. It follows for a Thomist that personhood is an analogical concept, and that personhood is most fully and truly realized in God, a community of Persons defined by their relations, by their pouring out and receiving of self.
And since God is pure act and self-subsistent being, it follows that personhood is the height of actuality. Persons are not an interesting side effect of the laws of the universe. Personhood is the foundation of existence, preceding everything else. Personhood is the culmination of existence, that toward which everything else strives. This is the knife that divides all philosophies and worldviews: either persons are the fundamental and supreme facts of the universe, or they are secondary or even illusory features of reality. (This is, I suspect, a more important question even than the currently fashionable question of consciousness.)
Jacob J. Andrews 
[…] Then we have: …whose center is everywhere and circumference nowhere. O great difference between bodily and intelligible spheres! The center of a bodily sphere can hardly be said to be anywhere at all, it’s so minuscule, while its circumference is understood to occupy several points. But the center of the Intelligible Sphere is everywhere, and its circumference nowhere. “Center” refers to creation, for just as Time is considered but a moment in comparison with Eternity, so the creature compared to the immensity of God is but a point or center[1]. Therefore God’s immensity is referred to as his circumference, since by ordering all things, he in a certain sense surrounds all things, and everything is embraced under his immensity. […]