Discovered by            C. Perrine
Date of Discovery        1905
Distance from Jupiter    11,737,000 km
Radius                   40 km
Mass                     8 x 10^20 g
Orbital Eccentricity     0.20719
Orbital Inclination      24.77°
Orbital Period           259.6528 days
Rotational Period        0.5 day
Density (gm/cm3)         ???

Elara shares a similar orbital inclination to Leda, Lysithea, and Himalia. They also orbit at roughly the same distance from Jupiter. These facts lead some to believe the four moons were once part of a larger asteroid pulled apart by Jupiter's gravity. Or one or more of them could be captured asteroids. Elara is the second largest of the four outer moons.

Sources:
NASA.gov
space.com