The Cumbrians have gone 11 League Two games without defeat since the start of the campaign - a club record - and are up to third in the table.
Carlisle's early pressure failed to yield too many clear-cut chances although Michael Raynes was inches off sliding home a Jason Kennedy flick-on after Danny Grainger swung over a corner from the right.
The home side were second best for periods before half-time, but improved after the break and Raynes forced Sam Walker to tip his close-range header on to the crossbar.
Raynes was involved again when Kennedy gave Carlisle the lead in the 50th minute, the defender heading Nicky Adams' corner back across the face of goal for Kennedy to force home.
Colchester missed a great chance to level the scores in the 66th minute when Sammie Szmodics found himself one-on-one with Gillespie but lifted the ball over the goalkeeper and over the bar from eight yards.
Szmodics then had a diving header cleared off the line, but substitute Ibehre relieved the tension in the 79th minute when his header from Grainger's corner on the left slipped through Walker's hands and into the net.
Report supplied by the Press Association.
Match ends, Carlisle United 2, Colchester United 0.
Second Half ends, Carlisle United 2, Colchester United 0.
Glen Kamara (Colchester United) wins a free kick in the defensive half.
Foul by Charlie Wyke (Carlisle United).
Attempt blocked. Dion Sembie-Ferris (Colchester United) right footed shot from outside the box is blocked.
Substitution, Carlisle United. Jamie Devitt replaces Michael Jones.
Attempt missed. Craig Slater (Colchester United) right footed shot from outside the box is close, but misses to the left.
Attempt missed. Denny Johnstone (Colchester United) right footed shot from the centre of the box misses to the left.
Substitution, Colchester United. Glen Kamara replaces Sammie Szmodics.
Foul by Reggie Lambe (Carlisle United).
Lewis Kinsella (Colchester United) wins a free kick on the left wing.
Attempt missed. Jabo Ibehre (Carlisle United) right footed shot from the centre of the box is high and wide to the right.
Attempt saved. Jabo Ibehre (Carlisle United) header from the centre of the box is saved in the centre of the goal.
Hand ball by Jabo Ibehre (Carlisle United).
Corner,  Colchester United. Conceded by Reggie Lambe.
Goal!  Carlisle United 2, Colchester United 0. Jabo Ibehre (Carlisle United) header from very close range to the top left corner. Assisted by Danny Grainger with a cross following a corner.
Corner,  Carlisle United. Conceded by Tom Eastman.
Substitution, Colchester United. Chris Porter replaces Drey Wright.
Corner,  Colchester United. Conceded by Jabo Ibehre.
Attempt blocked. Sammie Szmodics (Colchester United) header from the centre of the box is blocked.
Corner,  Colchester United. Conceded by Michael Raynes.
Substitution, Carlisle United. Jabo Ibehre replaces Shaun Miller.
Attempt missed. Craig Slater (Colchester United) right footed shot from outside the box misses to the left.
Corner,  Colchester United. Conceded by Michael Jones.
Corner,  Colchester United. Conceded by Michael Jones.
Attempt blocked. Drey Wright (Colchester United) left footed shot from outside the box is blocked.
Corner,  Colchester United. Conceded by Macaulay Gillesphey.
Attempt missed. Sammie Szmodics (Colchester United) right footed shot from the centre of the box is too high.
Substitution, Carlisle United. Reggie Lambe replaces Nicky Adams.
Substitution, Colchester United. Dion Sembie-Ferris replaces Tarique Fosu-Henry.
Attempt blocked. Drey Wright (Colchester United) right footed shot from outside the box is blocked.
Attempt saved. Drey Wright (Colchester United) right footed shot from the right side of the box is saved in the centre of the goal.
Attempt missed. Jason Kennedy (Carlisle United) left footed shot from outside the box is high and wide to the left.
Goal!  Carlisle United 1, Colchester United 0. Jason Kennedy (Carlisle United) right footed shot from very close range to the high centre of the goal following a corner.
Corner,  Carlisle United. Conceded by Lewis Kinsella.
Attempt saved. Michael Raynes (Carlisle United) header from the centre of the box is saved in the top left corner.
Corner,  Carlisle United. Conceded by Sam Walker.
Attempt saved. Danny Grainger (Carlisle United) left footed shot from outside the box is saved in the bottom right corner.
Luke Prosser (Colchester United) is shown the yellow card for a bad foul.
Shaun Miller (Carlisle United) wins a free kick in the defensive half.
Second-half goals from Jason Kennedy and Jabo Ibehre helped Carlisle beat Colchester 2-0 and extend their unbeaten start to the season.