We report the discovery of LSR0602+3910 , an L dwarf of class L1 .
The object was initially identified by Lépine et al .
( 2002 ) as a new high proper motion star lying close to the Galactic plane .
Its 2MASS J - K _ { s } = 1.43 is consistent with an L dwarf , which we now confirm spectroscopically .
In addition , we see a signature of Li I absorption , making LSR0602+3910 a brown dwarf , one of the brightest known ( K _ { s } = 10.86 ) .
Among L dwarfs it is second in brightness to the combined light of 2MASS 0746+20 , a close binary system .
We see no indication that LSR0602+3910 is a binary , although high-resolution imaging will be required to confirm this .
Spectroscopic and photometric distance estimates agree very well , placing LSR0602+3910 at d = 10.6 \pm 0.8 pc .
LSR0602+3910 was most likely missed in previous searches because of its proximity to the plane , the region that most searches avoided .
We estimate that some 40 % of bright L dwarfs are missed because of this selection effect .