You can't, there is a secret entrance round the back of the jailhouse however.
There is a second part to the underground jail... When you go in through the tunnel follow the path until you get to the larger cockroaches then head north until u see stairs, go up the stairs and in the room with the full size roaches will be a lever, pull the lever then go back down stairs and go through the jail door.
hope this is what you are looking for.
XweaselX
To enter the dungeon, players must bank all items. You do not need to have the Ring of Kinship with you; you only need it to form a party. There is a Dungeoneering Tutor and a Fremennik Banker standing at the entrance to the castle. Players who need to obtain the Ring of kinship for any reason, such as having lost it, should speak to the tutor to obtain one.
I have placed a link below in the "Related Links" section that should take you to the appropriate guide, if you read and follow it carefully, it should help you find what you need.
The only door that is open or can be opened is the one with a poster on the back wall, all the others cannot be opened.
in taverly dungeon: to get there ull need a key the key isn't tradeable but u can find it in the dungeon u just run furder into the dungeon until u come into the dark knights fortress there ull have to find the jail at the jail theres a guard who has the key to the prison door just kill him and pick up the key use the key on the PRISON door and talk to the guy whos in there hell give u the key to go to the blue drags
I think Cockroach soldiers. They're lvl 83 and can be found in the underground jail in Edgeville.
that depends on witch jail it is.
This key unlocks the door in the Taverley Dungeon, just past the Lesser Demons. To obtain the key, go to the southern area of the dungeon, with the Black Knights and Lord Daquarius. Kill the Jailer; use the Jail Keys he drops to unlock the door with Velrak the Explorer in it. As a reward for freeing him he will give you this key. There is also a Dusty Key respawn near where the Lava Eel fishing spot is located and is bought at the Legends' Guild for 1gp.
You right-click on the door and select the option to pick the lock. When you successfully do so, your out. Then, all that is left is to walk out the door past the sleeping guard.
The Jail or Dungeon!
South of Edgeville. There is a Jail trapdoor. Enter it, and peel back the poster in one of the open cells. Then, go to the eastern part of it and there will be some cockroach soldiers, level 89. They don't auto-attack, though.
It is called the Dungeon.
If you are talking about the bit the leads into the Dragons area, you will need a dusty Key, one of these can be obtained by going to the Room Full of Black Knights then On the East side of this room is a Jail Cell. To enter you must kill the guard outside, take the key he drops and use it with the door. Once inside you can talk to the Explorer who is locked inside and get the Dusty Key.
be a member and pickpocket as a random event
Do you mean jail? Prison is carcel (accent on the e). A jail is a calabozo, which is also the word for dungeon.
She's at the Jail to the east of Draynor Village