ACC/AHA New Blood Pressure Guidelines
and JNC7 Guidelines:
JNC7 and the new ACA/AHA blood pressure guidelines
The most widely used classification of blood pressure for adults over 18 years of age is from the 2003 Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) [1].

JNC7 Classification of blood pressure for adults:

Normal: Less than 120/80 mm Hg;
Prehypertension: Systolic between 120-139 or diastolic between 80-89;
Stage 1 Hypertension: Systolic between 140-159 or diastolic between 90-99;
Stage 2 Hypertension: Systolic greater or equal to 160 or diastolic greater or equal to 100 mm Hg
In 2017 the American College of Cardiology/American Heart Association (ACC/AHA) defined new guidelines for the detection, prevention, management and treatment of high blood pressure [2].

ACC/AHA Blood pressure categories in the new guideline are:

Normal: Less than 120/80 mm Hg;
Elevated: Systolic between 120-129 and diastolic less than 80;
Stage 1: Systolic between 130-139 or diastolic between 80-89;
Stage 2: Systolic at least 140 or diastolic at least 90 mm Hg;
Hypertensive crisis: Systolic over 180 and/or diastolic over 120, with patients needing prompt changes in medication if there are no other indications of problems, or immediate hospitalization if there are signs of organ damage.
It is important that you "Know Your Numbers", and understand the implications of the new guidelines.
[1] The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) https://www.nhlbi.nih.gov/files/docs/guidelines/jnc7full.pdf
[2] New ACC/AHA High Blood Pressure Guidelines Lower Definition of Hypertension, American College of Cardiology, Nov 13, 2017. https://www.acc.org/latest-in-cardiology/articles/2017/11/08/11/47/mon-5pm-bp-guideline-aha-2017