"Previous studies of undergraduate engineering students have raised questions of a student's engineering identity influencing their experience, both as an individual and also as part of a unique social culture. Aspects considered include motivation for initially selecting engineering as a major, persisting in engineering, navigating the curricular structures for degree completion, and intentions to pursue engineering in a form of professional practice beyond undergraduate studies. The current study used theoretical foundations from identity stage theory, originally introduced by Erikson in the 1950's, as a psychosocial perspective for identity based on both individual and social identification. Further, the transitional development period of emerging adulthood, introduced by Arnett in 2000, is used to frame the factors influencing undergraduate students today. A mixed method, cross-sectional study of undergraduate engineering students at the University of Notre Dame was conducted. A large-scale survey of all undergraduate engineering students, ~1100, yielded responses from ~700 students. Survey questions were based on a study approach defining adulthood by Arnett, but specifically applied to engineering identity as a parallel but unique instrument. Engineering identity from a student perspective was assessed, both in terms of self-identification (do engineering students consider themselves to be engineers?) and identifying factors that are "necessary" to be considered an engineer. (A qualitative inquiry followed to better inform our conception of engineering identity in terms of a sense of belonging to the College of Engineering as a whole.) Twelve student interviews across grade levels and engineering self-identifications were conducted as a collection of case studies. The results of the current study indicate that engineering identity is psychosocial as Erikson's theory would indicate. The personal student development, the "psycho" portion, takes place over time, and is clearly discernable between first-year students and other grade levels (sophomores, juniors, and seniors) but also takes place at different rates for individuals. Individual student experiences contribute to an overall sense of belonging to the college and engineering identity that relates to future career plans. The "social" portion of engineering identity was influenced by factors relating to how the institution identifies a student, in this case belonging to the College of Engineering."