Twilight Princess - Lanayru Province Poe Locations
This province has the most Poes in the entire game. Most of them can be acquired the moment you unlock the Poe Side Quest but the few found in the City In the Sky won't be acquired until a bit later in the game.
Poe #18 - Located in Zora's Domain
Now that we've made it to the Lanayru Province we're going to start at the very top and work our way down. That means Zora's Domain is our first destination! There are two Poes for you to uncover at Zora's Domain. Neither of them are found in the 'Throne room' like area where you first Warp in at.
Both of the Poes are found outside in the Waterfall area. The first of which is found on the same side of Zora's Domain that you find the Male Golden Dragonfly. It's the same side we traveled up our first time here as a wolf and coincidentally the same side we must travel up to reach Poe #19.
Poe #19 - Located in Zora's Domain
This Poe is found behind the Waterfall in Zora's Domain. You can actually see this Poe while standing at the same location you collected #18 if you have your 'Sense' on. In order to reach this Poe you'll need to follow Midna and jump up the side of the mountain; starting next to the entrance that leads to Snowpeak.
The Poe is only two jumps up and a little bit over, he's extremely easy to find still.
Poe #20 - Located in Zora's River
You can find this Poe in the same portion of Zora's River where Iza's Rapids Ride is (the place you get the Bomb Bag upgrades) as well as the Female Golden Dragonfly. This Poe is on a piece of land in the southern portion of this area.
Poe #21 - Located In Hyrule Field North of Castle Town
In the portion of Hyrule Field to the north of Castle Town you'll find this Poe wandering around on the bridge that crosses the river at night. He's right out in the open and extremely easy to find.
Poe #22 & #23 - Located In Hyrule Field North of Castle Town
Similarly in the same portion of Hyrule Field north of Castle Town you'll find an area in which you can dig while a Wolf that will lead you to an underground dungeon with a lot of Deku enemies as well as two Poes for you to grab.
The place you need to dig is found relatively close to the location where you find the Male Stag Beetle. Check my screen shots if you need some guidance finding it.
Poe #24 - Located in Hyrule Field Southwest of Castle Town
This Poe is found to the south of the Castle Town Warp portal in the ruins that overlook Lake Hylia. He's right out in the open and pretty darn easy to find.
Poe #25 - Located East of Castle Town
You can find this Poe just outside of the Castle Town exit opposite to where the Warp portal is. It's the same side that leads to Eldin Province, there's a side quest that you may or may not have done yet to repair the bridge over here so you may be unfamiliar with this side.
Regardless from Castle Town travel linearly towards the bridge until you find the Poe to kill.
Poe #26 - South of Castle Town in Hyrule Field
Much like the previous Poe you can find this one just outside the southern exit of Castle Town. He's found in the same exact area where you find the Female Golden Ladybug. You can't miss him!!
Poe #27 - South of the Great Bridge of Hylia
This Poe is a bit tougher than the previous ones. Again the fastest way to reach this one is to port to Castle Town and travel south to the Great Bridge of Hylia. Cross over the large bridge and continue south until you cross over another much smaller wooden bridge.
In the immediate area you'll find boulders that you can destroy and when you do so you'll reveal multiple Clawshot locations. The third platform you can Clawshot to has a chest on it which contains a purple Rupee. This platform is also where you'll find Poe #27.
Poe #28 - Located around Lake Hylia
Now that we've cleared the top of Lake Hylia it's time to do the bottom! Speak with Midna while in Wolf form to teleport to your Warp location at Lake Hylia. When you arrive look to the south, if it's night out you'll see a Poe floating in the distance. Jump over and dispatch of him.
Poe #29 - Located around Lake Hylia
The next Poe to capture at Lake Hylia is the one that you can find near Plumm, the speaking Parrot who is in charge of the Balloon popping minigame. If you're unfamiliar of where that is or what it is take a look at my screen shot for some guidance.
Poe #30 - Located around Lake Hylia
For this Poe you need to travel south from the Warp location and up the nearby wooden bridge as well as the ladder while in human form. The ledge you come across will have a Howling Stone on it as well as the destructible Boulder which leads to the cave containing the next three Poes.
You'll want to continue past this towards the large tower you see in the distance. This is where you'll find Poe #30.
Poe #31, #32 and #33 - Cave in Southern Lake Hylia
Time for the extremely easy batch of Poes at Lake Hylia! From where you port in at you'll want to travel a bit to the south and past the Howling Stone. You'll find a boulder that you can destroy with some bombs in the side of the mountain, it's shown in my screen shot below.
Destroy the boulder and enter the cave. Inside you'll find Poes #31, #32 and #33. **Before you come here** make sure you have Lantern Oil and a solid stock of Bombs. You'll need to use many of them to traverse these tunnels.
Note: All three of these Poes will be visible to you even if it was day when you entered the cave.
Poe #34 and #35 - Acquired through Flight by Fowl Mini Game
For these Poes you will need to play Falbi's Flight by Fowl game which starts nearby the Great Bridge of Hylia north of Lake Hylia. To reach Falbi's Flight by Fowl minigame you'll want to port to Castle Town and travel to the south.
When you reach the Great Bridge of Hylia instead of crossing the bridge follow the road in the other direction. Doing so will bring you to Falbi's house where you can participate in this minigame. For more information on the minigame itself and how to win the Piece of Heart please check out that guide.
As for the two Poes, #34 is found in the middle of Lake Hylia on the Isle of riches. You have to navigate your way here using one of the Cuccoos you get from Falbi's Minigame. The tier of this island that we're aiming for is the second, for more clarification take a look at my screen shot below.
Similarly in order to reach #35 you'll want to begin Falbi's minigame and make an immediate U turn landing on a platform just under his house. You'll find a Poe here at night that spawns overtop of a hidden cave with an Orange Rupee in it (defeat the enemies to make the chest appear).
Poe #36 - Located in "City in the Sky"
Note: Requires the Double Clawshot to obtain this Poe.
The first Poe for you to find in the City in the Sky dungeon is located on the side of the dungeon with the destroyed bridge. In the room just after where you find the first piece of heart <insert link> there is a large open room with a bunch of flying targets that you have to Clawshot onto.
The Poe is found in the far southern portion of this room located on an island. You have to Clawshot onto one of the targets nearby the crack in the wall and ride it close enough to reach the Clawshot target on the Poe island. If you need help finding this location use my screen shots as guidance.
You will also find the second piece of heart in the same room this Poe is in - not on the same island, however. If you're having difficulty finding this room I recommend you view that guide as well for additional screen shots which will be visual aids.
Poe #37 - Located in "City in the Sky"
Note: Requires the Double Clawshot to obtain this Poe.
This Poe is found in the part of the City in the Sky dungeon where you have to turn into a Wolf and walk across the tight ropes.