  I present a new census of the stellar population in the Chamaeleon I
star-forming region. Using optical and near-IR photometry and followup
spectroscopy, I have discovered 50 new members of Chamaeleon I, expanding the
census of known members to 226 objects. Fourteen of these new members have
spectral types later than M6, which doubles the number of known members that
are likely to be substellar. I have estimated extinctions, luminosities, and
effective temperatures for the known members, used these data to construct an
H-R diagram for the cluster, and inferred individual masses and ages with the
theoretical evolutionary models of Baraffe and Chabrier. The distribution of
isochronal ages indicates that star formation began 3-4 and 5-6 Myr ago in the
southern and northern subclusters, respectively, and has continued to the
present time at a declining rate. The IMF in Chamaeleon I reaches a maximum at
a mass of 0.1-0.15 M_sun, and thus closely resembles the IMFs in IC 348 and the
Orion Nebula Cluster. In logarithmic units where the Salpeter slope is 1.35,
the IMF is roughly flat in the substellar regime and shows no indication of
reaching a minimum down to a completeness limit of 0.01 M_sun. The low-mass
stars are more widely distributed than members at other masses in the northern
subcluster, but this is not the case in the southern subcluster. Meanwhile, the
brown dwarfs have the same spatial distribution as the stars out to a radius of
3 deg (8.5 pc) from the center of Chamaeleon I.
