They command six-figure salaries and lucrative benefit packages, yet some are moving on after only a few years on the job.

They are public-school superintendents, and some say they have the most rewarding but challenging jobs in education.

The increasing demands on schools chiefs coupled with better opportunities and retirements in recent years have created more vacancies than there are qualified candidates.

Across the region, Philadelphia, Camden, Haddonfield, Lower Merion and Radnor are among the districts searching for new chiefs in a dwindling candidate pool.

"It's a pretty active season," said Tom Templeton, director of School Personnel Services for the Pennsylvania School Boards Association, which is assisting at least 20 districts searching for superintendents, including New Hope-Solebury and Methacton in Montgomery County.

A search could take several months, or more than a year. In some cases, demand is driving up salaries, and some districts are sweetening their offers to land candidates.

Nationally, the average annual superintendent salary in 2005-06 was $116,000, but nearly $185,000 for larger districts, according to the American Association of School Administrators. In the region, the averages were $155,039 in Pennsylvania and $123,660 in New Jersey, according to data from the states' Departments of Education.

The highest salary in the region was paid to Paul Vallas, departing chief executive officer of Philadelphia's schools. This year, the job pays $275,000, but he's collecting $250,000 due to the district's budget deficit.

Four others - all in Pennsylvania - received salaries of $200,000 or higher last year, data show. The highest-paid in South Jersey was Daniel Hicks of Lenape Regional in Burlington County, who received $196,639. Hicks will leave at the end of his contract this summer.

Some districts, including Camden, have extended their searches, or allotted more time - as much as two years - to find the right candidate.

Typically, vacancies are attracting 10 to 20 applicants, compared with as many as 30 to 40 a decade ago, officials say.

The 6,900-student Lower Merion School District last month launched a national search to replace Superintendent Jamie Savedoff, who will retire when his five-year contract expires in February, spokesman Douglas Young said.

Savedoff gave the board ample notice to hire someone and facilitate a smooth transition, Young said. The board expects to offer a competitive salary. Savedoff's salary is $210,000.

"The hope is that there would be some attractive candidates who would be interested in working in a place like Lower Merion," Young said. The district has a $160 million budget and 1,200 employees.

Radnor, a similarly high-performing and wealthy district in Delaware County, is in the market for a superintendent after the resignation of Gary Cooper, whose salary was $198,450.

In New Jersey, more districts are turning to internal candidates to fill superintendent vacancies, said Jane Kershner, a field representative with the New Jersey School Boards Association. Lenape Regional promoted an assistant superintendent to the top spot.

New state laws have capped administrative costs and limit how much districts can pay superintendents. The state also mandates transparency on contracts and requires boards to disclose all financial terms and hold public hearings before hiring a superintendent.

"It used to be that some districts paid annuities, but we're not seeing that anymore," Kershner said. "They are being a little more conservative."

The Camden school board reopened its search after its first attempt failed to produce enough qualified candidates. The board has narrowed the field to two finalists with extensive experience in urban education: Bessie Young, a regional superintendent in Philadelphia, and Shelley Jallow, chief academic officer for the Prince Georges County (Md.) School District, were introduced at a public forum Thursday night.

The board suffered a setback last week when another candidate, William Penn School Superintendent Dana Bedden, withdrew his name because he is a finalist to become superintendent in Myrtle Beach, S.C.

Married and the father of three young children, Bedden said his decision was best for his family and "nothing against" Camden schools, which have been plagued by scandals and a criminal investigation into allegations of misspent district money and test-score cheating.

Districts seeking superintendents are often tapping into an already established network of school executives, said Judith M. von Seldeneck, chairman and CEO of Diversified Search, an executive search firm in Philadelphia. "You want qualified and capable people who have a track record."

The average tenure for a superintendent is three to five years. New Jersey's annual turnover rate increased to 21 percent four years ago, but dropped to 11 percent in 2005-06. Statistics were not available for Pennsylvania.

School officials blame the shortage of candidates on the aging population of experienced superintendents, increasing demands on them under the federal No Child Left Behind law, and pressure to meet state mandates. The job often requires long hours and activities during nights and weekends.

"You feel like you can only do it for so long," said Richard Coe, executive director of the Bucks County Intermediate Unit. "It's a never-ending job."

Coe, an educator for nearly four decades, is among several superintendents in the region who are retiring this year. In the last 12 months, six of the 13 superintendent jobs in Bucks County have turned over, he said.

The Haddonfield School District didn't expect to be searching for a replacement for Superintendent Joseph J. O'Brien after only two years. O'Brien was appointed executive director of the Chester County Intermediate Unit last month.

O'Brien, 56, said that he had hoped to retire from Haddonfield, but that Chester County was a dream job that would allow him to spend more time with his family in Media. He said he had declined jobs with at least two other districts that tried to lure him from Haddonfield with more money.

"There's a supply-and-demand problem with quality superintendents," O'Brien said.

Chosen from a field of six candidates, O'Brien will oversee 12 districts in the county and earn $210,000 annually - $35,000 more than he received in Haddonfield. From 1999 to 2005, he was superintendent in the Springfield School District in Delaware County.

O'Brien will replace John Baillie, who is retiring in June after 25 years at the helm. Baillie, an educator for more than four decades, earned $228,000.

Elsewhere in South Jersey, Moorestown hired John Bach as its superintendent from a field of about 30 candidates, ending a five-month search. Bach, a Moorestown resident, is an assistant in the Hopewell Valley Regional District in Mercer County.

Board President Don Mishler said that the Moorestown district had hired a search consultant, and that interim Superintendent Timothy Brennan had agreed to stay at least two years if needed while the board searched for a permanent replacement for Paul Kadri, who resigned in 2006.

"It was easy because we knew our backs weren't against the wall," Mishler said.

Contact staff writer Melanie Burney at 856-779-3876 or mburney@phillynews.com.