Which rivalry do you think is the most intense in Rugby League? I have a few candidates in mind:

Rhinos vs. St. Helens - The two most succesful teams in the SL, one from Lancashire and one from Yorkshire, it's only natural that they hate each other!

Rhinos vs. Hunslet - The Leeds Derby, you can call it. Although Rhinos have much bigger fish to fry than a bunch of tier three bitters, Hunslet supporters seem to despise the Rhinos.

Rhinos vs. Bulls - Maybe the most famous rivalry in RL, although not as heated since Bradford have been going down the pan. Leeds and Bradford, as cities, hate each other beyond rugby.

Hull FC vs. Hull KR - Two teams from the same city, in the same league, go figure.

Any such list which lacks Quins vs Catalans reveals only ignorance on the part of the poster.

Missed saints vs wigan.

But i'd have to say the hull derby.

Only one derby.
The Hull and Rovers rivalry is comparable to Celtic/Rangers. (hatred)
Just ask Sean Long how big it is, and he's only played in a friendly derby (although in front of 16000 fans)

Rovers and Hull simply because it divides familys and there is no escaping it. You have to work with fans from the opposite team and the banter is continuous

Goroka v Unggai Bena in Papua New Guinea.

They actually kill each other over a knock-on.

Me thinks that happens in the city of Wakefield, maybe not the same scale, three clubs in the city.

Skirlaugh v West Hull.

1 club in the CITY 2 clubs in towns in the councils boundry, not city

How often do Trinity play Eastmoor and Stanley Rangers though

That's nowt. When Ngukafuka play kikingooli, a red card and they eat you...

Widnes/Crusaders