  We report the discovery of two damped Ly-alpha absorption-line systems (DLAs)
near redshift z=1 along a single quasar sightline (Q1727+5302) with neutral
hydrogen column densities of N(HI) = (1.45\pm0.15)\times10^{21} and
(2.60\pm0.20)\times10^{21} atoms/cm2. Their sightline velocity difference of
13,000 km/s corresponds to a proper separation of 106h_{70}^{-1} Mpc if
interpreted as the Hubble flow (Omega_m=0.3, Omega_Lambda=0.7). The random
probability of such an occurrence is significantly less than 3%. With follow-up
spectroscopy, we find [Zn/H] = -0.58\pm0.15 (26.5% solar) and -1.32\pm0.28
(4.7% solar), respectively, and [Cr/H] = -1.26\pm0.15 (5.5% solar) and
-1.77\pm0.28 (1.7% solar), respectively, which is evidence for depletion onto
grains. Follow-up IR images show the two most likely DLA galaxy candidates to
have impact parameters of 22h_{70}^{-1} kpc and 32h_{70}^{-1} kpc if near z=1.
They are significantly underluminous relative to the galaxy population at z=1.
To investigate the possibility of additional high-N(HI) absorbers we have
searched the SDSS database for z>1 quasars within 30 arcmin of the original
sightline. Five were found, and two show strong MgII-FeII absorption near z=1,
consistent with classical DLA absorption approx 37% of the time, but almost
always N(HI) > 10^{19} atoms/cm2. Consequently, this rare configuration of four
high-N(HI) absorbers with a total sightline velocity extent of 30,600 km/s may
represent a large filament-like structure stretching over a proper distance of
241h_{70}^{-1} Mpc along our sightline, and a region in space capable of
harboring excessive amounts of neutral gas. Future studies of this region of
the sky are encouraged.
