  We perform empirical fits to the \emph{Chandra} and \emph{XMM-Newton} spectra
of three ultraluminous X-ray sources (ULXs) in the edge-on spiral galaxy NGC
891, monitoring the region over a seventeen year time window. One of these
sources has been visible since the early 1990s with \emph{ROSAT} and has been
observed multiple times with \emph{Chandra} and \emph{XMM-Newton}. Another has
been visible since 2011. We build upon prior analyses of these sources by
analyzing all available data at all epochs. Where possible \emph{Chandra} data
is used, since its superior spatial resolution allows for more effective
isolation of the emission from each individual source, thus providing a better
determination of their spectral properties. We also identify a new transient
ULX, CXOU J022230.1+421937, which faded from view over the course of a two
month period from Nov 2016 to Jan 2017. Modeling of each source at every epoch
was conducted using six different models ranging from thermal bremsstrahlung to
accretion disk models. Unfortunately, but as is common with many ULXs, no
single model yielded a much better fit than the others. The two known sources
had unabsorbed luminosities that remained fairly consistent over five or more
years. Various possibilities for the new transient ULX are explored.

High Energy Astrophysical Phenomena