We present high resolution ( R=50,000 ) spectra at 2.2 \mu m of 16 young stars in the \rho Ophiuchi dark cloud .
Photospheric features are detected in the spectra of 11 of these sources , all Class II young stellar objects .
The 5 featureless spectra consist of 2 Class I , 2 Class I.5 , & 1 Class II .
One star , GSS 29 , is identified as a spectroscopic binary based on radial velocity variations .
The radial velocities for the remaining sample are consistent with ^ { 12 } CO and H _ { 2 } CO gas velocities and further confirm the membership of the sources in the \rho Ophiuchi cluster .
For the 10 spectroscopically single Class II sources , we measure effective temperatures , continuum veiling , and v \sin i 
rotation from the shapes and strengths of atomic photospheric lines by comparing to spectral synthesis models at 2.2 \mu m. We measure surface gravities in 2 stars from the integrated line flux ratio of the ^ { 12 } CO line region at 2.3 \mu m and the Na I line region at 2.2 \mu m. Although the majority ( 8/10 ) of the Class II stars have similar effective temperatures ( 3530 K \pm 100 K ) , they exhibit a large spread in bolometric luminosities ( factor \sim 8 ) , as derived from near–IR photometry .
In the two stars where we have surface gravity measurements from spectroscopy , the photometrically derived luminosities are systematically higher than the spectroscopic luminosities .
The spread in the photometrically derived luminosities in our other sources suggests either a large spread in stellar ages , or non-photospheric emission in the J–band since anomalous and significant veiling at J has been observed in other T Tauri stars .
Our spectroscopic luminosities result in older ages on the Hertzsprung–Russell diagram than is suggested by photometry at J or K. Most of our sources show a larger amount of continuum excess ( F _ { Kex } ) than stellar flux at 2.2 \mu m ( F _ { K* } ) , substantially higher in many cases ( r _ { K } \equiv 
F _ { Kex } /F _ { K* } = 0.3–4.5 ) .
The derived veiling values at K ( r _ { K } ) appear correlated with mid–IR disk luminosity , and with Brackett \gamma equivalent width , corrected for veiling .
The derived v \sin i rotation is substantial ( 12–39 km s ^ { -1 } ) , but systematically less than the rotation measured in Class I.5 ( flat ) and Class I sources from other studies in Ophiuchus .
In four stars ( Class I and I.5 sources ) , the absence of any photospheric lines is likely due to large continuum excess and/or rapid rotation if the stars have late–type photospheres .