Meaning of “along” - Learner’s Dictionary

along

preposition uk us /əˈlɒŋ/
DIRECTION

A2 from one part of a road, river, etc to another:

a romantic walk along the beach
NEXT TO

B1 in a line next to something long:

a row of new houses along the river
PARTICULAR PLACE

at a particular place on a road, river, etc:

Somewhere along this road there's a garage.

(Definition of “along preposition” from the Cambridge Learner’s Dictionary © Cambridge University Press)