Kjalvegur. |. Kjalvegur (officially known as Route F35) is a highland road in Iceland, with a length of 168 km (104 mi), crossing Kjoelur, kjÃ¶lur a plateau in the highlands Of, iceland at an elevation of aboutâ600 700, metres from north to. southjalvegur. |. Kjalvegur (officially known as Route F35) is a highland road in Iceland, with a length of 168 km (104 mi), crossing Kjoelur, kjÃ¶lur a plateau in the highlands Of, iceland at an elevation of aboutâ600 700, metres from north to. south