What are the locations of the Warp Zones in Super Mario Bros. The Lost Levels?

In which levels are the Warp Zones located in Super Mario Bros. The Lost Levels (The original SMB2 and not that Doki Doki Panic clone.) and how do you get to them?

Here is a list of all 11 warp zones and how to get to them, copied from MarioWiki (under CC-BY-SA):

There are nine forward Warp Zones and two backward Warp Zones in the game:

• World 1-2: A little ways into the underground level, the ceiling will hang slightly lower than it usually does. If the player jumps on top of an invisible coin block, she/he can make a vine appear by hitting the brick directly on the right. If the player climbs this vine, they will enter an area that has a Warp Zone leading to World 3. There are two more Warp Zones near the end of the level. Both can be accessed by going past the pipe leading to the surface. (This can be done by using the moving platforms to get onto the ceiling.) Past this pipe, the player will find two more pipes with Piranha Plants in them, and then a staircase leading to a World 2 Warp Zone. To access the other Warp Zone, the player must go down the first of the two pipes with a Piranha Plant in it. This will lead to another underground room with a lot of water-filled pits and more pipes with Piranha Plants. Near the end of this room, the player will find a wall that can be cleared by using two invisible coin blocks. Past this wall, there is a Warp Zone leading to World 4.

• World 3-1: This level has a backward Warp Zone that leads to World 1. It can be accessed by using a green spring near the end of the level to jump over the flagpole. If a player accidentally finds this Warp Zone, they can avoid getting sent back to World 1 by jumping into a small pit on the left of the screen, resulting in a life loss, rather than getting warped back. This Warp Zone can also be accessed by going down the first pipe of the level, and then going through the underground area.

• World 5-1: Near the end of the level, there is a vine that leads to a Coin Heaven. After going through the Coin Heaven, the player will fall and land near a Warp Zone that leads to World 6.

• World 5-2: This underground level has two Warp Zones in it. In order to access the first Warp Zone, the player should eventually come across a set of platforms moving upwards. On the left side of these platforms, there is one block that juts over the edge. Hitting this block underneath will cause a vine to sprout out the top. Climbing this vine will take Mario up to the surface where he will find a Warp Zone leading to World 8. In order to access the second Warp Zone, the player must use the same set of moving platforms to get onto the ceiling and run past the pipe leading to the surface, just like in 1-2. If these instructions are heeded, the player will find a Warp Zone leading to World 7 at the very end of the area.

• World 8-1: There is a pipe mid-level that leads to an underwater area. The pipe at the end of this underwater room leads to a backward World 5 Warp Zone. Unlike in 3-1, however, this Warp Zone does not have a pit or any other way for Mario to kill himself. If a player happens upon this Warp Zone and does not want to go back to World 5, she/he can wait until time runs out, which will result in a life loss and take the player back to the beginning of the level.

• World A-2: The Warp Zone in this underground level can be accessed by finding a way onto the ceiling and running past the pipe leading to the surface, just like in 1-2 and 5-2. This Warp Zone leads to World B.

• World A-3: There is a springboard and a Red Koopa Paratroopa just before the flagpole in this level. If the player jumps off the springboard, and then bounces on the Red Koopa Paratroopa to get over the flagpole, she/he will then have to run a far distance, but will eventually come across a Warp Zone leading to World C.

• World B-4: When the player sees the first few Bowser Flames coming toward her/him, there is a pipe with a Red Piranha Plant shortly after. Going down this pipe will take the player up to the surface where she/he will find a Warp Zone leading to World D.

Here's a pretty comprehensive list which describes exactly how to reach each Warp Zone. There are actually quite a few (10 in total), many more than the first game.

EDIT: From the link above.

Where are the warp zones locations in Super Mario Bros: The Lost Levels? Our walkthrough guide will show you were to find them. Note that using a Warp Zone will forfeit your ability to access World 9, so use them at your own discretion!

Unlike the original Super Mario Bros., this sequel features many more Warp Zone secrets, even multiple Warp Zones per level (the first game featured only three Warp Zones in the entire game). These will come in handy and help you advance forward to a later section of the game. Helpful because The Lost Levels is much more difficult than the first SMB.

To that end, not only does SMB: The Lost Levels feature Poison Mushrooms which will kill you instead of help you, but it also features Warp Zones that take you BACKWARDS to a previous world instead of forward. This is only a good thing for those looking to increase their score if they are playing competitively.

Super Mario Bros Lost Levels Warp Zone #1 – level 1-2 There are three Warp Zones on this level. This one is found just beyond some Goombas, where there is a Buzzy Beetle in between a Pipe with a Piranha Plant and a staircase. Above the Buzzy Beetle is an invisible block. Coming up out of it will be a vine that you can take to the Warp Zone. This Warp Zone will take you to World 3.

Super Mario Bros Lost Levels Warp Zone #2 – level 1-2 The second Warp Zone leads to World 2. You will find it by simply running to the right along the ceiling of the level. There are multiple ways to get onto the roof, so simply find one and run beyond the end-level exit pipe to find this Warp Zone.

Super Mario Bros Lost Levels Warp Zone #3 – level 1-2 The final Warp Zone in this level is found on the way to Warp Zone #2, where you are running along the roof. Before you reach that Warp Zone to World 2, you’ll find two Piranha Plant Pipes. Enter the first one and you’ll find a secret area. Now jump onto the blocks where the Question Mark Block is and leap across the hot lava. Make sure you are small Mario and run over the lava to where you see a Red Koopa Troopa. Above it is an invisible block. With another invisible block a bit to the right and above that one. Use these to leap to the top of the brick wall, run to the right and you’ll enter another Warp Zone with a Warp Pipe that takes you to level 4. Phew!

Super Mario Bros Lost Levels Warp Zone #4 – level 3-1 To reach it either go down the first silver pipe you see, or jump over the flagpole at the end of the level. -Thanks for the tip Supermariopuzzler!

Super Mario Bros Lost Levels Warp Zone #5 – level 5-1 This Warp Zone will take you to World 6. You’ll find it near the end of this stage when you come across three Red Paratroopas. Near them are two rows of bricks. A vine is inside the end brick to the right. If you’re small you can reach the vine using the Paratroopas. This will lead first to a Coin Heaven bonus section then to the Warp Zone that warps you to World 6.

Super Mario Bros Lost Levels Warp Zone #6 – level 5-2 This is a simple Warp Zone to find. Simply get up to the ceiling and run all the way to the right past exit pipe. This Warp will take you to World 7.

Super Mario Bros Lost Levels Warp Zone #7 – level 5-2 To get to this Warp Zone that takes you to world 8, notice a floating structure right before the raising and lowering Donkey Kong-style elevator platforms. Hit this structure by riding a platform and leaping from the platform as it rises. A vine will pop out and you can use the elevators to reach it. You’ll then find a Warp Zone that takes you to World 8.

Super Mario Bros Lost Levels Warp Zone #8 – level 8-1 You will find this Warp Zone which takes you to level 5, beyond the third Hammer Bros. in this level. After passing the Hammer Bro., you’ll find a right-side-up Pipe that takes you to an underwater section. You’ll find another pipe to the right, take it and you’ll come up from the water with the Warp Zone Pipe to the right. However instead of warping you FORWARD, this Warp Pipe takes you back to level 5!

Super Mario Bros Lost Levels Warp Zone #9 – level A-2 In this level is a Warp Zone to World B. As usual, to find this one you’ll need to run along the ceiling of this level, all the way to the right, past the exit pipe.

Super Mario Bros Lost Levels Warp Zone #10 – level A-3 This Warp Zone takes advantage of an infamous Super Mario Bros. trick and converts it into a legit secret. To find this Warp Zone, use the Spring Board at the end of this level to JUMP OVER THE FLAGPOLE at the end of the stage. Keep running right and you’ll find a Warp Zone that warps you to World C.

Super Mario Bros Lost Levels Warp Zone #11 – level B-4 The final Warp Zone is found within a Bowser’s Castle level! This is a first for the series. There is a part that you will reach that looks like it is a “maze section” where you must run through the correct routes to proceed . . . but in actuality it’s just a ruse. You’ll see a pipe within. Go down the pipe and you’ll reach a Warp Zone that will take you to World D.

This video will guide you to finding each and every Warp Zone in Super Mario Bros.: The Lost Levels.