NOvA is a long-baseline neutrino oscillation experiment, which consists of two finely-segmented liquid-scintillator detectors

operating 14 mrad off-axis from the NuMI muon neutrino beam. With an 810 km baseline, the combined measurements of muon neutrino disappearance and electron neutrino appearance allow the determination of neutrino oscillation unknowns, namely the mass hierarchy, the octant of the largest neutrino mixing angle, and the CP violating phase.

In this dissertation, I present the joint analysis of $\nu_\mu\to\nu_\mu$ and $\nu_mu\to\nu_e$ oscillation data with an exposure of

$8.85\times10^{20}$ protons on target on the 14 kton detector. It includes the estimation of neutrino energy distributions in the far

detector using near detector data constraints, details of the implementation of the simultaneous fit of \numu and \nue samples, and

the effect of systematic uncertainties on the measurement of oscillation parameters. I also discuss NOvA's projected sensitivity to determine the mass hierarchy and discover CP violation in future analyses with increased exposure and the addition of

antineutrino datasets.

With 66 electron neutrino and 126 muon neutrino candidates, the best

fit to the data corresponds to the normal mass hierarchy, $\Delta m^2_{32}=2.44\times 10^{-3} eV^2/c^4$, $\sin^2\theta_{23}=0.56$,

and $\delta_{CP} = 1.21\pi$, with the allowed regions $\Delta m^2_{32} \in

[2.37,2.52]\times 10^{-3} eV^2/c^4$, $\sin^2\theta_{23} \in [0.43,0.51] \cup

[0.52,0.60]$ and $\delta_{CP} \in [0,0.12\pi] \cup [0.91\pi,2\pi]$ at the

68.3\% C.L. Our data disfavor maximal mixing by 0.8$\sigma$, $\delta_{CP}

= \pi/2$ in the inverted hierarchy at higher than 3$\sigma$, and the

entire inverted mass hierarchy at the 95\% confidence level.