  Two string-like solutions to the equations of motion of the low-energy
effective action for the heterotic string are found, each a source of electric
and magnetic fields. The first carries an electric current equal to the
electric charge per unit length and is the most general solution which
preserves one half of the supersymmetries. The second is the most general
charged solution with an event horizon, a `black string'. The relationship of
the solutions to fundamental, macroscopic heterotic strings is discussed, and
in particular it is shown that any stable state of such a fundamental string
also preserves one half of the supersymmetries, in the same manner as the first
solution.
