  Distance estimates based on low-resolution spectroscopy and Two Micron All
Sky Survey (2MASS) J magnitudes are presented for a large sample of 322 nearby
candidates from Luyten's NLTT catalogue. Mainly relatively bright (typically 7
< K_s < 11) and red high proper motion stars have been selected according to
their 2MASS magnitudes and optical-to-infrared colours (+1 < R-K_s < +7). Some
LHS stars previously lacking spectroscopy have also been included. We have
classified the majority of the objects as early-M dwarfs (M2-M5). More than 70%
of our targets turned out to lie within the 25 pc horizon of the catalogue of
nearby stars, with 50 objects placed within 15 pc and 8 objects being closer
than 10 pc. Three objects in the 10 pc sample have no previously published
spectral type: LP 876-10 (M4), LP 870-65 (M4.5), and LP 869-26 (M5). A large
fraction of the objects in our sample (57%) have independent distance
estimates, mainly by the recent efforts of Reid and collaborators. Our distance
determinations are generally in good agreement with theirs. 11 rather distant
(d > 100 pc) objects have also been identified, including a probable halo, but
relatively hot (T_eff = 13000 K) white dwarf (LHS 1200) and 10 red dwarfs with
extremely large tangential velocities (250 < v_t < 1150 km/s). Altogether,
there are 11 red dwarfs (including one within 70 pc) with tangential velocities
larger than about 250 km/s. All these objects are suspected to be in fact
subdwarfs, if so, their distances would be only about half of our original
estimates. The three most extreme objects in that respect are the K and early M
dwarfs LP 323-168, LHS 5343 and LP 552-21 with corrected distances between 180
pc and 400 pc and resulting tangential velocities still larger than about 400
km/s.
