The conjectural conclusion is about 1500 miles long! (4)

I believe the answer is:

ural

I'm a little stuck... Click here to teach me more about this clue!

'1500 miles long' is the definition.
I can't tell whether this definition defines the answer.

'the conjectural conclusion is about' is the wordplay.
'is about' indicates a hidden word (the clue goes around or about the answer).
'URAL' is hidden in the letters of 'conjectural conclusion'.

Can you help me to learn more?

(Other definitions for ural that I've seen before include "Russian river flowing into the Caspian Sea" , "Asian flower" , "2,400 km river flowing through Russia and Kazakhstan into the Caspian Sea" , "River feeding Caspian Sea" , "Mountain range in Russia" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.