There are, first, two types of "power" (there are, in fact, three, but the first is simply that by which a thing exists at all - X has it, and exists, or X does not have it (is functionally self-contradictory, etc.) and doesn't exist. There is no "amount" to this and so it cannot be "patterned"). The two types (which can be patterned) are:
Brí - intrinsic, inherent power. This may be "developed" or "atrophied" but can not, substantially, be changed in potential amount.
Bua - power that is gained or lost, depending upon actions.
Landscape has, as does everything else, both types. Skipping, for the moment, that these may be "keyed" to certain affinities, in summary a place's brí is linked to it's basic nature. Isolated hills, sea cliffs, etc., have higher intrinsic brí. A place's bua is determined (and changed) by what occurs there (a major battle, etc.). In fact, it is more complicated because humans deliberately pick high-brí places for their religious and, less often, political centers, thus layering bua over the already existing brí. While usually this occurs so that the bua develops the brí, the opposite can occur. The Mallacht Dhealúis, great curse of bareness, laid upon Teamhair by a coven of 13 Irish saints is an example. In this case, the saints' own brí-empowered bua was used to drain and ward-restrict the bua of "Tara" and hinder its bua. The site once had a great deal of both, but it now has fairly low bua, while retaining brí in a form difficult, but not impossible, to access.
Brí may be "keyed" by its basic nature, but bua is far more likely to be keyed because it is gained or lost by specific actions. Personally keying may involve not only one's own bua being compatible but season, time of day, and so forth, since such bua is highly contextual.
Brí, and far more often bua, may become "keyed", that is it may gain affinity or malevolence toward other types of brí/bua (some people may, for example feel "at home" in a place that others will feel uncomfortable in). In a few cases, a place will have general malevolence (the term frithbhuachán is used for either a place or thing that drains bua and assaults brí. (see also the note on Drombeg below.)
Taking brí and bua together, no man-made-like grid patterns these powers. The "map" of a country's power does not resemble a geometric human network, but a naturally occurring one, resembling maps showing rainfall or physical elevation. That is, there may be sharp demarcations, or gradual ones. Entire areas may be low in both bua and brí (except in small limited areas, a high bua level is unlikely to occur without at least moderately high brí, although the reverse is not true: indeed the feeling of "awe" experienced at some natural "wilderness" sites results from them having quite high brí, although they may have only minimal bua.
Teamhair: there is still a great deal of keyed brí here. Both the author and others have worked here to specific activate the brí, and support the remaining bua while adding to it. These activities have caused changes, including, it appears, counter-reaction, perhaps deliberately but more likely as a result of the Mallacht Dhealúis reacting to being opposed (the outward manifestations include the statue of Patrick which a co-worker of the author magically cracked being soon taken down, but the Irish government having begun to newly limit access).
Tlachtga: the hill of the Brune Samhna or Samhain fire ritual contains mangled bua and brí.
Newgrange: traditionally a cómhla bhreac or gate to the Otherworld, it has brí and bua, but has had so much "alternate" bua attempted to be imposed on it, that these are reduced (by the last is meant that many people have directed buanna (bua-plural) of radically conflicting types at Newgrange - imagine a Christian shrine for peace being the scene of a battle between Moslems and Hindus at which immediately afterward a group of atheists put on a comedy show - or a commercial for cigarettes during a documentary on the dangers of smoking!). Newgrange, like Teotihuacan, has had tens of thousands of people actively directing their totally incompatible (with it, but as importantly with each other!) energies at it and the original balance is quite, literally, stewed.
Maynoth: no brí to speak of, but high bua specifically keyed to the dominance of the Christian church. (if you are pagan and go, one of the few places you need wards.)
Aran Islands: Dún Aoghusa has high natural brí, more than its bua, but the latter is also quite high. Dún Dubh Cathair has both high, but less bua (in total and as ratio to brí) than Dún Aohghusa. On Inish Maen, Dún Conor exhibits more bua than brí. Other areas, here unnamed because of on-going workings, on the Islands contain at least as high, probably higher levels of brí.
Sligo Area: the entire area around Sligo has fairly to very high brí, and moderate to high bua. Knocknarae, Carrowmore, Kesh, Ben Bulben, Magh Tuiread (no.2), Carrowkeel, Deerpark, Kreevykeel, etc., all have good levels of both brí and bua.
Donegal: Sliabh Liag is fairly high brí with a little bua, of a rather hard to define type, mixed in. "Malin Head" (or Fíorcheann na hÉireann, the True Top of Ireland, to give it its proper name) has little bua, but massive brí. Indeed the highest brí is separated from the mainland by a violent gash in the earth which always appears to be a deliberate separating-itself from tampering. The Grianán of Aileach has muted brí and moderate bua.
Belteny: high bua and brí, with the bua, if you can key to it, somewhat higher.
Kerry: the Kenmare River estuary, Inbher Scéine has moderately low brí, but can exhibit superb bua if properly keyed (in this case, all the seanchais and the author's own experience are explicit: this is where Amhairghin first arrived in Ireland). Dunmore Head, the most westerly point of Ireland has strong brí. The author is unable to comment on the general bua due to personally imposed keying.
West Cork: the only time the author visited the "most photographed stone circle in Ireland", Drombeg, he could hardly rate the brí for the extremely negative iarrairdeall (one of several druidic methods of "sensing" different types of "vibes", beyond the scope of this article). This was not bua in the general sense, but a reaction of the site to its bua having been (recently, but not by him!) assaulted. This did not appear frithbhuachán in the usual sense, i.e. not a "keying". Such an occurrence is rare but makes accurate readings difficult.
Dublin: the Garden of Remembrance, comparatively meager in brí, has a very high level of bua, surprisingly for a modern monument with some Christian elements, keyed specifically to pagan druidism. (The most Christian element is the cross-shaped pool, almost all of the rest, including the golden dedication and the magnificent "Children of Lir" is thoroughly - that it is in downtown Dublin, awesomely - pagan. It is, in effect, a "war memorial", but one like none other in the world, and it honors ALL of those "who died for Irish freedom", by the intent of its designers or by the gods having a hand, in its motifs honoring the Tuatha Dé Danann and Amhairghin's Men of Míl more than it does those of the Easter Uprising.